400 hp 383 build help

-
Fisher

Fisher

Old Guy with a Cool car.
Joined
Jul 22, 2012
Messages
1,950
Reaction score
951
Location
Regina Sask Canada
I am looking to buy another car. Its a B body, 67 Coronet 500,with a factory 383 2bbl car with 727 and 8-3/4. this is going to be a driver when i am done, with 3.55 gears etc.

I would like to build a mild 400 Hp cruiser, can this be done with cast heads? I have a set of decent 906 heads under the bench, will buy headers, and an rpm performer intake. Just want this to be pump gas motor with mild cam. I know some of you have built similar combos, I have tried the search function is't bring up what i want.
 
Shouldn't be a problem, the 383 HP engine was rated at 335, so headers, a more modern cam, and maybe some bowl port work should make for a nice streetable package
 
Fisher said:
I am looking to buy another car. Its a B body, 67 Coronet 500,with a factory 383 2bbl car with 727 and 8-3/4. this is going to be a driver when i am done, with 3.55 gears etc.

I would like to build a mild 400 Hp cruiser, can this be done with cast heads? I have a set of decent 906 heads under the bench, will buy headers, and an rpm performer intake. Just want this to be pump gas motor with mild cam. I know some of you have built similar combos, I have tried the search function is't bring up what i want.
Click to expand...

Easily done! Don't over cam it! Go solid mechanical cam. Keep header tubes smallish like 1-3/4". Get a distributor you can tune the timing curve, get the initial up and in quick. 750 carb. Now heads are gonna be bottle neck! Honestly stock 906 head prob won't get you to 400hp. Nice valve job and mild port? Maybe. For cost of head work your damn near into cheap alloy heads and cutting 75lbs off the nose. More guys will chime in here but my 383 runs really hard and I love it!



 
This is kinda what it would take to get you into the 350-360 HP range. Add what you think to get the other 40-50 HP. Oh, don't worry, lots of others will tell you what you need.

The slug 400 on the dyno.
 
Just finished a similar project for my Scamp . Started with a 383-2 : 1968, 383Magnum TRW forged pistons = 335 h.p. 1976 (915) heads with larger valves and bowl work . don't spend more than $600 on heads or else get alloy set , good for 20+ h.p.. Headers : T.T.I. 1 3/4-1 7/8 " = 30h.p.. Cam : somewhere near .500 lift hydrolic flat tappet = 25 h.p.. Roller rockers = 20h.p.. 750 c.f.m. carb. =10 h.p.. Block prep. and balance = 10 h.p.. You are there with 440 h.p. and no sweat . I think the compression ratio is right on for pump gas . If you can't get premium fuel in your area you can drop the compression ratio by using a .042" head gasket . Camshaft selection is critical here . Can't go wrong with the Mopar Performance line or the ones from Comp Cams . I'm a big believer in balancing . Makes for a happy motor . You can add headers later if you are on a budget . They are expensive but they work like heck . I did mine for less than $6K U.S. not including headers . Good luck , Tom
 
383Scampman said:
Just finished a similar project for my Scamp . Started with a 383-2 : 1968, 383Magnum TRW forged pistons = 335 h.p. 1976 (915) heads with larger valves and bowl work . don't spend more than $600 on heads or else get alloy set , good for 20+ h.p.. Headers : T.T.I. 1 3/4-1 7/8 " = 30h.p.. Cam : somewhere near .500 lift hydrolic flat tappet = 25 h.p.. Roller rockers = 20h.p.. 750 c.f.m. carb. =10 h.p.. Block prep. and balance = 10 h.p.. You are there with 440 h.p. and no sweat . I think the compression ratio is right on for pump gas . If you can't get premium fuel in your area you can drop the compression ratio by using a .042" head gasket . Camshaft selection is critical here . Can't go wrong with the Mopar Performance line or the ones from Comp Cams . I'm a big believer in balancing . Makes for a happy motor . You can add headers later if you are on a budget . They are expensive but they work like heck . I did mine for less than $6K U.S. not including headers . Good luck , Tom
Click to expand...

If it were only that easy, if only................
 
IQ52 said:
This is kinda what it would take to get you into the 350-360 HP range. Add what you think to get the other 40-50 HP. Oh, don't worry, lots of others will tell you what you need.


The slug 400 on the dyno.
Click to expand...

Thats crazy how much of a hit in performance the 2 bbl was.

Ya OP just go 9:1, air gap and a slightly hotter cam (10 degress) and call it a day.

And if building from scratch and budget allows drop a turned down 440 cranks for 426-438 cid for an extra 50-60 lbs-ft of torque.
 
I already have a 525 hp 426 low deck in my duster. 383 with 440 crank. It has good manors, at the same time it is a bit much for a daily hwy car.
 
Spoke to Edelbrock today, they have a top end kit, for a 383 an RPM performer kit made 421 hp and 417 tq, with 9.5-1 compression. be perfect for what i am doing.
 
be careful with hp numbers...and the cam.
a big cam may hit your number at higher rpms but be very disappointing on the street.
lo rpm torque is important.
 
The lunati cam in my 426 is. on dyno made 552 peak tq and 516 tq at 2900 rpm.car never stops pulling.

  • Advertised Duration (Int/Exh): 272/280
  • Duration @ .050 (Int/Exh): 243/251
  • Gross Valve Lift (Int/Exh): .546"/.566"
  • LSA/ICL: 110/106
  • Valve Lash (Int/Exh): .016"/.016"
  • RPM Range: 2600-6800
 
You must log in or register to reply here.
-

Back
Top