OT: Book on Flathead 6 Engine - Performance Modifications

[fedoragent]

Folks,

Does anyone know if there is a book on performance modifications that can be done to a FHD6 engine? Specifically a P15 would be nice but not required.

Thanks,

FG.

[Andydodge]

Lots of luck.......lol.........I'd really like one also but doubt whether such an animal has ever existed..........HOWEVER.........have you had a look at Pete "Blueskies" website that he created when he did up his 50 Plymouth?.........I have printed out virtually his whole site and keep it for a great source of reference information.........as a general guide for what can be done to these engines its basically the standard stuff........bore, balance, extra carbs, ie 2 or 3 , better exhaust via split manifolds, headers, twin systems, updated ignition via twin points or Electronic, lighten the flywheel, hotter cam grind, mill cylinder head to increase compression, install a finned head, upgrade oil pump, Chev valves( not sure what ones) are supposed to be an improvement...........generally speaking the cheapest way to get some more herbs is to have the head milled & upgrade the induction/carby setup......my 1941 201 cube powerhouse was 95 throbbing neddies at 6.7:1 compression when built in 1941.........my understanding that apart from a 2 barrel carby, 1/8th extra bore size or 29 cubes extra in total and running 8.0:1 compression in 1959 the same basic engine had 140 neddies, an increase of 45 or close to 50%..............but I don't think much over 160-170hp is achievable without some serious modifications..........check out what Earl Edgerton in Ca. doing with his F head conversions etc for Bonneville........anyway just my thoughts.......have attached a pic of my long term 230 engine build.......hopefully will be done soon........andyd

[louie the fly]

FG, I've heard a bit about 2 barrel carbs versus 2x1's or 3x1's. Some say it's a better option as it's easier to get & keep the engine running sweet. Fairly generic really. You'd know what I mean if you've ever tried to keep a GTR-UX1 in good reliable tune! From what I've been able to find lately this forum is the best place to find info, be it a stocker or a hottie.

Andy, you know, I've been in the metal trade for nearly 30 years and I've never lightened a flywheel. Have you had yours done? If so, did they just guts out the back and remove a heap of material then re-balance it? Mate, if I could get mine to 150+ HP I'd be happy.

Louie

[Don Coatney]

There is one book that I have heard of. I do not own it nor have I read it.

ISBN: 087938459X / ISBN-13: 9780879384593

How to Build Chrysler, Plymouth, Dodge Hot Rods

by Geoff Carter, Smith Tex, Leroi Smith

Expect to pay $100.00 and up...

http://www.abebooks.com/9780879384593/Build-Chrysler-Plymouth-Dodge-Hot-087938459X/plp

[louie the fly]

I think it doesn't cover the flatheads though. Have a quick look here. http://www.amazon.com/Build-Chrysler-Plymouth-Dodge-Rods/dp/1878772171#reader_1878772171

Says it has something about hemis & slant 6's, but no flatties.

[james curl]

I have the book and Tex discusses the hemi in great detail as well as the other V8 engines. He devotes four pages to the slant six with some pictures of flat head speed equipment. No write up of any type on the flat six in the engine section. I paid $17.95 for mine in 1990 and that's really all it is worth. If you want to install a MoPar V8 in your MoPar then he has quite a bit of information for you.

[Plymouthy Adams]

with the exception to the location and max lift of the valves..the engine is as basic as any other..items that change the compression ratio, cam profile, induction, ignition and exhaust are pretty much common across the board. While I will not try to detract from Tex Smith as I have no knowledge of the man, but the Mopar Performance engine build book has plenty of pages on every aspect of the engine from stock to all out race part nubers etc etc who knows more about the Mopar engine than the folks who developed it...there is even a slant 4 out there if you folks want that..yep..special engine buiot on 1/2 of the small block 8...with all the performance part to go with it...

Edited July 15, 2010 by Tim Adams

[Don Coatney]

I once owned an International Scout with a slant 4. Very rugged and dependable engine. The V-8 was a 304 CID engine. The slant 4 was a 152 CID. Simply the V-8 cut in half.

[Plymouthy Adams]

number of companies has done this over the ages...I was always dissapointed not to find the other half of the slant 6..could you imagine the V12 this puppy would have made..

[Young Ed]

Tim I've also heard the 3.9l v6 in my dakota is a 318 minus the rear two cylinders and that the v10 was a 318 with 2 more added on.

[Plymouthy Adams]

that is true Ed..the LA engine has been the work horse and building platform for many years..I had no clue about the slant four till I was just doing some reading..never made production car level, cast and built as strick race engine for special modified class..being the same slugs and rods..head etc...ought to be able to punch up rather nicely..

[Young Ed]

All good engines. My little 3.9 is a couple drives to work away from turning 192K. Burns and leaks a little oil but its still running strong.

[Andydodge]

Louie, have not got that far into my engine build yet due to a severe lack of funds.........lol....but a lightened flywheel was something i was going to seriously look at, as my understanding is that it with a good balance job will help to get some higher revs outa these ol' girls.....the bored out 318 Poly I have in my 40 Dodge had a decent balance on it and has always been a smooth reving engine. As its an auto, the balance included the torque converter and with a 35/75 cam & crossram setup with a pair of holleys it used to see 6500 when held in the gears at Sydneys old Castlereagh Dragstrip in the 80's.........oh to be young & stupid agin'.............lol...........andyd

[Don Coatney]

....but a lightened flywheel was something i was going to seriously look at, as my understanding is that it with a good balance job will help to get some higher revs outa these ol' girls................andyd

I dont think you will get higher revs but you will get the revs faster. Circle track racers have used this trick for a long time.

[greg g]

There is a fellow on the HAMB who has documented his efforts to try to wring 200 HP out of a 230 flatty. You can probably still find it either in the geeral forum or the one for the HAMB dragsters. He documented several dyno pulls with various carb and ehanust set ups. I believe his highes number was 180, but he experiencd a miss that limited rpms, and his thought was that there was a bit more to be had.

I have had mine on a chassis dyno. I limited it to 65 MPH. with 50 HP added for wind drag, it put 127 HP to the rear wheels. The dyno has a lookup with cars and trucks going back to the 60's. The 50 HP was pretty typical for medium Pickup trucks which we figured were similar in frontal area to the Plymouth. My engine is a 230, .030 pistions, .050 of the head/deck, dual carbs on a fenton intake, and single ehaust with 2 in id pipe thoughout. My engine is out of a 56 Plymouth the factory rated it at 125 at the flywheel with 7.6 to 1 cr. So if I am getting 127 at the wheels, means my mods have over come the 20% loss associated with drive line friction. I would think a 20% bump on any engine is significant. If the guy on the HAMB can pull 200 flywheel ponies, I would think for a normally aspirated engine, he is pretty close to max on the old flathead design.

When we were in Detroit a couple years back we were talkig with a couple of fellows who were Engineers at Chrysler (wonder if they are still working) and were talking possibilities for flatheads. as they were both building 40's mopars. the coversation visited turbo charging and fuel injection. The stuff from the turbo 2.5 and or 2.6 (mitsubishi engine) Mopar of the late 70's early 80's being the donor vehicles.

If you look at that system of getting extra horses, gains of 40 to 50 hp should be easy to find. There is a web article from a fellow who turboed a 198 inch Studebaker champion flathead with good results.

So money, time, and your inginuity seem to be the limiting factors, oh yea and the long stroke design also.

You can also take a peak at the Hudson forum by stuff from the Hudsonator regarding flath 6 power upgrades.

If folks are getting 25 HP out of what was a 6hp Briggs and stratton,for go carts and microds, any thing is possible.

Edited July 15, 2010 by greg g

[blueskies]

...have you had a look at Pete "Blueskies" website that he created when he did up his 50 Plymouth?...

Here's my "book", for what it's worth

http://www.50plymouth.com

Pete

[greg g]

here is a link to some of he HAMB discussion but a visit to MOPARSLED's user page would bring up all his posts.

http://www.jalopyjournal.com/forum/showthread.php?t=298125&highlight=plymouth+flathead+dyno

[Flatie46]

I believe there's some tricks that haven't been tried or thought of yet. Like Greg said, "Money, time and inginuity". If I had more of these three I'd have a little skunk works project going on myself. I don't think I'd be interested in lightening the flywheel for one I was gonna drive much. The way I understand it, these engines had alot of torque but the HP was a bit low. Torque gets 'em rolling and helps with driveability [pulling hills without down shifting and such]. I think if you lighten the flywheel you might gain some HP but you'll loose torque in a trade off. I also think you'll shorten the life of the engine if you lighten the flywheel alot. This is just my opinion and I may be wrong. I will say this, an old guy that lives out the road from me has raced all his life. His brother was well known locally for racing back in the 50's and 60's[he died racing years ago]. The man stops by every once and a while and asks about my Plymouth. I asked him once what his brother done to make 'em win. He said they bored em big and built em loose, very light flywheel[ I think he said aluminum] big carb and header also custom ground cam. He said they wouldn't last very long but if my brother didn't blow it up he would usually win. He added keeping your foot off the brake will put you in the front quicker than anything.

[Plymouthy Adams]

as Enzo always said, brakes just slow you down..

[fedoragent]

Folks,

Because of work, I haven't been able to read everything until this morning. I had considered the lightened flywheel and the dual barrel carb. In my vw days, our options were simple. New cams,lightened flywheel, MSD 6AL with Msd Flamethrower, dual barrel, dual carbs up to 48 pict. With that and an upgraded braking and suspension you were gold. I have wondered if some of theories could be put to use on a flattie. Time will tell.

[~Waiting~]

http://victorylibrary.com/L6-SV.htm

[~Waiting~]

Also, I don't know if the limitations on the L6 are the same as a Ford V8 flathead but getting 200 hp out of the Ford would cost you thousands of dollars.

[Plymouthy Adams]

cost ya a pretty penny just to get it to equal a flat head mopar 6...the old flathead Ford was a smooth puppy though..and the cats meow when introduced..it survived longer than it should have and then sold to the French, later the French company fell under Chrysler rule so effectively, Chrysler made the last of the Ford flathead 8's

[greg g]

And made quite a few engineerng improvements regarding the overheating issue and sensitivity to fuel pressure.

[Plymouthy Adams]

kinda like the BASF logo: "We don't make the product, We make it Better"