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JSabah

Flathead engine work

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I've been restoring a '49 Plymouth Woody and have now started to think about the engine.  While I've thought about putting a newer modern crate engine in, I think I've come to the conclusion that I'd like to keep the original look to the car and engine bay (ie flathead) but Id like a bit more power than the stock 6 cyl Flathead has.  Does anyone have any recommendations for a engine builder in the Van Nuys/Los Angeles are who could give me some ideas of what is able to be done and that can take on the work?  Also any suggestions as to how far (or not too far) to go with it is appreciated.  Im just looking to be able to comfortably get on freeways and travel the hills/canyons.  I realize that this may also affect the trans and rearend.  Ive already decided to change to a 12 volt system.  Thank you.

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If nothing else I call the guys.

They specialize in Mostly Ford products But do all flat motors .  Or just ask them for Mopar flat six builders they know and respect in the L.A. area. They are probably the most expensive shop but do many, many top flat motor builds.

Just a thought,

DJ.

 

https://handhflatheads.com/

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if you plan to keep it a flathead, good on you thats awesome. you will get more looks at your car over one with a v8. as for what to due to your flathead, the dual carb/ dual exhaust is usually everyones everyone thing to do. whats good about it is it has nothing really to do with the internals of the engine. the next thing would be milling the head for more compression. this is good because you can take the head off while the engine remains in the car. those 2 options i would expect about a 10-20% gain in performance over stock depending how far you go. going more involved in the engine wont gain u more then what those 2 things will net you, a more hotter reground cam would help but then your into more of a tear down on the motor. if you are pulling out the motor, going to a modern transmission with an over drive will get you cruising down the freeway. im going to be putting a t5 5 speed behind my flathead. i already have the adaptor to mate it to my stock bell housing. switching in a newer rear end from a 60s-70s car would get you better freeway driving but you would lose low end.

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Edgy aluminum head with 9:1 compression is #1 approach to increasing Mopar flathead six power for casual driving. Incrementally more power can be gained with transistorized ignition, twin barrel carburetor, and radiator fan delete (use electric fan instead). Don't overlook importance of fine tuning ignition advance and jetting the carburetor. 

 

With 20-25% more power, 3.4 ratio rear axle will allow cruising at 60-65 mph at comfortable engine rpm. As to transmission, flathead six and 3 speed transmission is a match made in heaven.

 

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On 4/9/2019 at 4:58 PM, DJ194950 said:

If nothing else I call the guys.

They specialize in Mostly Ford products But do all flat motors .  Or just ask them for Mopar flat six builders they know and respect in the L.A. area. They are probably the most expensive shop but do many, many top flat motor builds.

Just a thought,

DJ.

 

https://handhflatheads.com/

H&H flatheads are extemely expensive and might be be too interested in doing the flathead six IMHO.

I got my 265 done at JMS racing engines in El Monte.  Basic rebuilt and the price was fair.  They did slightly mill the head, decked the block slightly to resurface and got a reground cam.

Going with a triple carb intake, dual exhaust, electronic ignition, T5 transmission and a ‘73 Body 7 1/4 rear end.

Edited by 40desoto
Grammar

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17 hours ago, sser2 said:

 

 

With 20-25% more power, 3.4 ratio rear axle will allow cruising at 60-65 mph at comfortable engine rpm. As to transmission, flathead six and 3 speed transmission is a match made in heaven.

I had 3 different 3 speeds transmission in my 38 Coupe, all had problems with 1st gear from years of use.      I wish you could drive my 38 Coupe now with the 5 speed transmission, a great improvement, even with a 82hp engine...

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Is adding A/C  a realistic option? Engine is out of the car. Probably going with a machined head to get the compression up, duel carbs and electronic  ignition....

Edited by JSabah

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The most difficult problem with AC is that all existing condensers are too wide, as they were designed for modern style cars. Finding space for compressor and re-designing belt drive would be another challenge. 

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32 minutes ago, sser2 said:

The most difficult problem with AC is that all existing condensers are too wide, as they were designed for modern style cars. Finding space for compressor and re-designing belt drive would be another challenge. 

I cannot concern with this.....I respectfully disagree...while the compressor adapter for the flattie is involved..it is not at all difficult, expensive or power robbing with the newer rotary compressors on the market today,.  The condensers are NOT in any manner too large and the belt issue can be addressed in a couple of manners.    There are evaporator units that are combination heater/ac that is no more a footprint that the stock heaters.....

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2 hours ago, Plymouthy Adams said:

I cannot concern with this.....I respectfully disagree...while the compressor adapter for the flattie is involved..it is not at all difficult, expensive or power robbing with the newer rotary compressors on the market today,.  The condensers are NOT in any manner too large and the belt issue can be addressed in a couple of manners.    There are evaporator units that are combination heater/ac that is no more a footprint that the stock heaters.....

On the belt issue, I've been considering power steering and A/c opportunities myself.  And, discovered that the crankshaft belt pulleys I had laying around off a 60s poly motor have the same bolt pattern as the 56 Plymouth core engine I'm using..  So there may be a lot of pulleys available of various offset/depths to help with that.  I think the decision has been made to do power steering and use a hydroboost for braking.  Probably a Chevy Astro.

 

Most modern condensers are parallel flow while a lot of the older ones where series. The point is, I'm not sure if horizontal orientation versus vertical would make a difference.  Anyone know for sure?

If it doesn't there would be a lot of options. 

One thing I do know, the small fitting should be on the bottom.  Large on top.  Gas in, liquid out.

On my very first 'cobbled together from parts' A/c install, I made that mistake.  High side pressures were enormous, just before a fitting and hose parted company.

It was easier to route them the way they were installed.  Didn't make it right.  1970, it was a '65 dart HP235, 4 spd.  wish I still had it.

 

One other lesson from that experience.  Install a wide open throttle A/c shut off.  For the flattie that provides a power boost when needed, on the 235, it keeps the compressor from grenading at 6000rpm!

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3 hours ago, kencombs said:

One other lesson from that experience.  Install a wide open throttle A/c shut off.  For the flattie that provides a power boost when needed, on the 235, it keeps the compressor from grenading at 6000rpm!

 

 

the newer parallel flow condensers are made to be efficient with the R134a refrigerant and should be your first concern to upgrade if retrofitting a R12 system.  It will function and usually function well with the old style condenser especially in a Mopar as they were still using expansion valve.  those that make use of the fixed orifice systems may see some erratic head pressures depending on compressor speed, system demand and ambient temps.    I would be as much if not more concern of the 265 grenading at 6000 ...lol

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Stay with the flattie and my experience is dual carbs helped the most then the head and improved compression ratio then the split exhaust manifolds. I bored my motor .040  any good machine shop  can perform this task and be sure the ignition system in good shape electric fuel pump to maintain constant fuel pressure. My wagon moves down the road way better than a stock one and gets 20 mpg and tons of looks when I raise the hood

2C953406-760B-427C-B4DA-C2546BBFB887.jpeg

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She’ll cruise all day at 75 and I did last years power tour 3000 Miles 

has factory overdrive 1800 rpms@  70mph

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I am in the middle of writing the specifications for what will hopefully be the last incarnation of my Desoto power plant.

 

So far I am looking at the following:

 

1. 265 either sleeved to STD or bored to 10-15 over.

(When you raise the compression the bore increase causes there to be less space between the cylinders. With higher compression, OVER TIME, you can have head gasket failure.  I did at about 60K miles. This engine was decked and bored 40 over. The head was NOS and had a cleaning pass on it to make sure it was flat.)

 

2. The engine will have a HEI from Langdon's and a throttle body injection system. (Two injectors each on one hole of an Edmunds dual 1BBL manifold).

 

3. On the big Chrysler 8 and the LWB Desoto which have larger steering boxes and larger steering arms, a 1969 Pontiac Wagon (Saginaw) steering chuck fits the splines and I will use that thanks to Don Smith and his research.

 

4. I will use an electric water pump at the base of the radiator and 4 small fans as a pusher. Not using an engine pump and fan will help with belts and access on the front of the engine.

 

5. A/C will be a high efficiency scroll compressor. Item 4 makes this possible and also helps with item 3. I will use a remote canister power steering pump.

 

6. Transmission. Some may have seen my post on that.  I am leaning toward a 4L60E transmission as all the shift points can be set via the computer and not having to machine governor weights as would be the case with a 700R4.  Also, some of the computers allow you to have a toggle switch to change from program A to Program B on the fly. With the 5500 pound Desoto that would be good as I could have a "flatland" and a "mountain" shift program.

 

7. Head.  I may use one of Earl's heads if the new guys in Montana ever have them back in stock. I will also use one of his cams if they are also grinding them again. The one I got from Earl for my 1949, which is his one up from stock, work fine in the '49.

 

8. I will be having custom made pistons.  I want to lighten the load as well as use a more modern ring arrangement. I have noted that after about 35K miles that cylinder pressure starts to drop. If one measures the bore one sees that it starts to tapper a lot.  I talked with several engine builders, men in their 80's, and they all said the long stroke coupled with the heavy pistons is the issue.  Their recommendation is to lighten the piston and go with different rings.

 

9. The ass of the cam has no bearing. The block wears and causes lower oil pressure.  I will bore that hole and use a steel or oilite bearing in there.

 

10. Rods will been very carefully rebuilt, including having ARP make the special 265 bolts. (on my 251, I used ARP 351 Ford Cleveland rod bolts and re-worked the head and nut surfaces for them and they have been fine for 65K miles and a lot of that at WOT for the 5500 pound car).

 

11. Dual cast exhaust.

 

That is my basic outline. One person wrote that he thought he was getting 25% more power, I think that may be a little optimistic. I will be happy if I can hit the Dodge Truck 136 HP mark.

 

James.

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5 hours ago, James_Douglas said:

I am in the middle of writing the specifications for what will hopefully be the last incarnation of my Desoto power plant.

 

So far I am looking at the following:

 

3. On the big Chrysler 8 and the LWB Desoto which have larger steering boxes and larger steering arms, a 1969 Pontiac Wagon (Saginaw) steering chuck fits the splines and I will use that thanks to Don Smith and his research.

 

4. I will use an electric water pump at the base of the radiator and 4 small fans as a pusher. Not using an engine pump and fan will help with belts and access on the front of the engine.

 

5. A/C will be a high efficiency scroll compressor. Item 4 makes this possible and also helps with item 3. I will use a remote canister power steering pump.

 

That is my basic outline. One person wrote that he thought he was getting 25% more power, I think that may be a little optimistic. I will be happy if I can hit the Dodge Truck 136 HP mark.

 

James.

 

Great list - with many interesting discussion topics - but I have one question. If going to all that trouble with electric fans, electric water pump, etc... why use a belt driven power steering pump with a remote canister? Electric power steering pumps are getting to be more common and could further help clean up your engine belt drive system. Simply tuck it away out of sight and route the lines as you see fit. Anyway just some food for thought.

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38 minutes ago, HotRodTractor said:

 

Great list - with many interesting discussion topics - but I have one question. If going to all that trouble with electric fans, electric water pump, etc... why use a belt driven power steering pump with a remote canister? Electric power steering pumps are getting to be more common and could further help clean up your engine belt drive system. Simply tuck it away out of sight and route the lines as you see fit. Anyway just some food for thought.

or, just use electric power steering.  Lots of them available cheaply.

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I’ve mentioned this before on other posts, but since you are going through the expense of custom pistons and you want to squeeze every bit of power reliably, I would look at using a longer rod out of a shorter stroke engine.  There are a lot of benefits to doing so and the cost of the pistons should be the same. 

 

FWIW 

Adam

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13 hours ago, James_Douglas said:

 

10. Rods will been very carefully rebuilt, including having ARP make the special 265 bolts. (on my 251, I used ARP 351 Ford Cleveland rod bolts and re-worked the head and nut surfaces for them and they have been fine for 65K miles and a lot of that at WOT for the 5500 pound car).

 

 

James.

By the time you get this done, it will probably be too late for me to take advantage, but I will be interested to know if you succeed.  A couple of years ago, I sent ARP a 265 bolt and asked them about making up bolts.  They are very specialized, and ARP said they had never made any bolts for the 265, and had no bolts that could easily be adapted.  I asked them for a ballpark cost to make such bolts, and they said it would be at least a few thousand dollars, maybe more.  At that point, I stopped my query.  After some research and queries on this forum and others, I found that most people who are not building race or hot rod engines just re-use the stock bolts, as long as they don't look damaged.  I even called George Asche, who has raced many of these engines for decades, and he said he re-uses his stock 265 bolts and has never had a failure, even with 5500-rpm (or more) operations.  So I reassured myself with that, and decided I'd re-use the stock bolts.

 

If you have better news than that, I'd really be interested to hear about it.  I still haven't reassembled my engine, so it's not too late at this point, but if it's going to be another six months before bolts are ready, or if they are going to be $1000 per set of 12, then it probably won't be in the cards for me.

 

If they do end up making some bolts, one thing to consider is whether they will be able to achieve the proper curvature of the underside of the bolt head, so that it will fit correctly into the curved, recessed socket of the rod.  Maybe it's not a big deal to get this feature correct, but it's something that had crossed my mind.

Edited by Matt Wilson

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On ‎4‎/‎22‎/‎2019 at 10:06 PM, Matt Wilson said:

By the time you get this done, it will probably be too late for me to take advantage, but I will be interested to know if you succeed.  A couple of years ago, I sent ARP a 265 bolt and asked them about making up bolts.  They are very specialized, and ARP said they had never made any bolts for the 265, and had no bolts that could easily be adapted.  I asked them for a ballpark cost to make such bolts, and they said it would be at least a few thousand dollars, maybe more.  At that point, I stopped my query.  After some research and queries on this forum and others, I found that most people who are not building race or hot rod engines just re-use the stock bolts, as long as they don't look damaged.  I even called George Asche, who has raced many of these engines for decades, and he said he re-uses his stock 265 bolts and has never had a failure, even with 5500-rpm (or more) operations.  So I reassured myself with that, and decided I'd re-use the stock bolts.

 

If you have better news than that, I'd really be interested to hear about it.  I still haven't reassembled my engine, so it's not too late at this point, but if it's going to be another six months before bolts are ready, or if they are going to be $1000 per set of 12, then it probably won't be in the cards for me.

 

If they do end up making some bolts, one thing to consider is whether they will be able to achieve the proper curvature of the underside of the bolt head, so that it will fit correctly into the curved, recessed socket of the rod.  Maybe it's not a big deal to get this feature correct, but it's something that had crossed my mind.

 

I have not in fact sent them a bolt yet. I called and talked with them and they said it was not a big deal.  But, I suspect that once they saw one that it will be.

 

One thing I have been thinking of having a rod and piston set up done that will clear and that has a design that a modern bolt will clear.  I will also look into if there is any meat to cut on the block so that a larger head on the bolt will clear. I suspect that MOPAR did the bolt so they did not have to cast another block. They also would  not want to spend the labor to grind a block for clearance. 

 

I have just been told today that in August, I may well have to have some serious back surgery. If that comes to pass, I will have to put off the car work until 2020.

 

Between now and summer, I will get the engine down to the short block and take a look at the actual clearance.  I used ARP 351C Ford bolts on the 251 that I have been driving. We worked the rod bolt faces to use them.

 

James

 

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On 4/24/2019 at 5:14 PM, James_Douglas said:

 

I have not in fact sent them a bolt yet. I called and talked with them and they said it was not a big deal.  But, I suspect that once they saw one that it will be.

 

One thing I have been thinking of having a rod and piston set up done that will clear and that has a design that a modern bolt will clear.  I will also look into if there is any meat to cut on the block so that a larger head on the bolt will clear. I suspect that MOPAR did the bolt so they did not have to cast another block. They also would  not want to spend the labor to grind a block for clearance. 

 

I have just been told today that in August, I may well have to have some serious back surgery. If that comes to pass, I will have to put off the car work until 2020.

 

Between now and summer, I will get the engine down to the short block and take a look at the actual clearance.  I used ARP 351C Ford bolts on the 251 that I have been driving. We worked the rod bolt faces to use them.

 

James

 

If you have surgery, I hope it goes well, with a full and speedy recovery.  As for the rod and piston idea, I'm sure you can make something work.  I suspect it would cost a lot, but you never know.  You might be able to come up with something reasonably priced.  I seem to recall Tim Kingsbury mentioning that he has had aftermarket rods made, but they were pricey (in the thousands of dollars, I believe).  The rods and bolts for these engines are hard to find and often expensive when you do.  There is a potential clearance issue with the lower end of the block, where the oil pan attaches, but I don't think that's where you're talking about.  The early 25" blocks have to be modified in this area, but the later ones were cast with the necessary clearance.  I thought the clearance concern for the rod bolt heads was with the camshaft, but I could be wrong.  You seem to be thinking it is with the block casting.  Anyway, good luck with it all.

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It’s back ... now I get to get it back in. Decided to go with an Offy intake and duel carbs as well as duel exhaust. Other than that 30 over, electric fuel pump

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