Real numbers

[Frank Elder]

265 to 218...modified

What kind of numbers can be expected for horsepower?

I have read 60 to 90 over on cylinders,50 to 70 on shaved head and block., Full flow headers with dual carbs, how far can you go before becoming unreliable?

Aggresive cam profiles, what is the wear and tear?

Happy Hallow's Eve!

[Andydodge]

Well the last of the 230's, 1957-59 have 8:1 compression and 130hp, add a 9:1 finned Edgy head, twin carbs, twin outlet exhaust, HEI dissy, balanced rotating assembly, electric fan(engine driven fan deleted), strong tailwind..........I'd like to think my eventual 230 that I am getting bits for should put out 160-170hp.........maybe......on a good day.......and a good tailwind........lol......andyd

[Don Coatney]

Go here.

http://www.jalopyjournal.com/forum/showthread.php?t=298125

And here.

http://www.jalopyjournal.com/forum/showthread.php?t=238372

[Andydodge]

Don....O/k then.........a VERY BIG TAILWIND..........lol......rethink those figures........how about 140-150hp.........maybe.......with that hoped for tailwind.......just had a look at the 6 on the dyno on youtube.....sounds mean.....Don.......what cam have you got in your Plymouth?........also is yours a 23 or 25" block?.......andyd

[Don Coatney]

Don....O/k then.........a VERY BIG TAILWIND..........lol......rethink those figures........how about 140-150hp.........maybe.......with that hoped for tailwind.......just had a look at the 6 on the dyno on youtube.....sounds mean.....Don.......what cam have you got in your Plymouth?........also is yours a 23 or 25" block?.......andyd

I sent my stock cam to Earl Edgerton for a new profile. I now have 260 duration @ .410" lift on both the intake and exhaust valves. My engine is a Desoto long block bored .030 over for 255CI displacement.

[greg g]

I posted some numbers to the thread based on three chassis dyno pulls at a regional college automotive lab. Several numbers were guestimated during the initial setup. Such as HP at 50 mile per hour. I guess this is to simulate wind resistance. Having no Idea what that number was we left it set at what they were using for modern cars. I think it was 25. If that number was off, it would effect the number. I also limited the pull to 65/70 mph. rather than run a peak power pull. (the cars proceeding mine on the dyno were running 85 to 90 mph to get their peak numbers.)

Also these numbers are at the wheels not at the flywheel where the factory ran their numbers.

So if you take my 75 add the 25 for hp at 50, that make 100 then add the 20% for drive line losses that puts 120 at the flywheel. Mine is a 56 engine that war rated at 125 by the factory.

I am runing + .030 pistons, .050 total off the head and block, and dual carters on a Fenton intake. Stock cam single exhaust with a dynomax turbo flow muffler. My car easily keeps up with traffic, pulls highway hills no problem, and accelerates from 45 to 70 with lots of grunt.

It also keeps up with the Coatney car without breaking a sweat.

It would seem that your planned modifications will add 10 to 15 HP over the stock level.

[Frank Elder]

Those are not my future plans, I was more interested in the durability of these engines when modified to the very edge of their tolerances.

ie; how much is too much? Overkill is in the eye of the beholder, everyone's ideas differ of course.

[greg g]

I guess If I were gonna do one near the ultimate edge, I would go with a turbo. Long stroke and flathead = limited rpms and limited breathing. So a turbo with a TB Fuel injection unit could be the way to go. The bottom ends are strong, but could use a little help with oiling so cross drilling the crank and bosting oil flow is probably a must. Keep the compression ratio miled and let the turbo do the breathing and help with the CR when its in the load zone.

I thas been mentioed that .090 milling is OK but required premium fuel. I would thing that if you kept it about 8 to 1 and then added the turbo boost you could get even more squeeze than just machining would do. Bigger valves might do the trick also. The limiting factor will probably be the head gasket between the siamesed cylinders. So part of you parts hunt would be a solid copper head gasket. or Machining the block for cylinder O rings.

[Frank Elder]

I have a 392 with O-rings, works really well. I guess the bottam line is that you could pay to play and still never attain more than say, 200 plus HP.

[greg g]

I guess that is why they went the V8 OHV route, more power.

[Frank Elder]

I'm sure you are correct, I want you guys to know this is not a put down I love my L-head 6, it will be dependable and get us around for many years to come.

Next summer is when the engine is budgeted for freshening up probably a rebuild kit, 30 over pistons, true the deck, and shave the head.

Don turned me onto dual points so we are definately going in that direction.Thanks for all the input guys!

[Andydodge]

Well, as mentioned on another post I have stuck the langdon HEI in and I reckon that it plus the strong tailwind experienced this afternoon, me leaning forward whilst piloting, with windows wound up and air vent closed an extra 2.5hp was experienced in its full majesty.......jees I'm a wanker........lol........andyd

[Frank Elder]

I always look forward to your jokes andy! What if you put 200 mph[nascar]tape on your car would you go faster? lol

[Plymouthy Adams]

Frankie...if you use speed tape (duct tape here in the south, every ladies purse has at least one roll in her favorite color) and cover the seams along the hood opeing etc and cut down the wind resistance..you can be assured of three things, loss of tape, loss of time applying the tape and an extremely ugly car...that is all...

[Frank Elder]

Then the car will match the owner!

My seams need fixin'

I lose everythingI

I,m not going to be on the cover of GQ

EVER!

Not to mention I,m not as not as fast as I once was.

[Andydodge]

Tape, Tape..........I forgot the tape.........another .75 hp..........