randy72

OK guys, here's what I've got going together....If anyone can give me the results, I would much appreciate it.

SBC 383 stroker
Ported 1970 LT1 heads 2.02/1.60
9.8:1 Compression
Roller rockers (1.5)
Hyd. Roller cam (.509/.528 222/230 @ .050 112 LC)
LT1 aluminum intake
Holley 750 or correct LT1 780 (undecided as of yet)
Port matched and extrude honed 2.5" exhaust manifold-needed for factory appearing drag racing...can't use headers.. I know it's probably going to cost me 30 horsepower
2.5" exhaust

Thanks in advance. Also if anybody is bored and wants to run a desktop drag simulator on it, It's going into my 72 Vette. 4 spd, 3.70 gears, 3350 lbs. w/driver.

Ganey

NO pgm. Assuming well built about 400.
IF Dynomax headers, larger heads even w/ a Performer intake 430+ HP.

:cool:

mountainmotor

Ganey,
Another good hit from experience :)

That is a good combination.Should run well!

MikeC

If no one else does, I'll do it when I get home from work.

Sounds like its going to be an amazing engine.

randy72

Thanks, I would certainly appreciate that. I'm estimating 400 HP and about 400 tq, but I'm curious to see where at in the RPM range.

Lt1er

Your cam is on the mild side. I run a solid 238/248. Your compression is also low. I'm running @10.5 with 186 casting double hump heads. I took the time to polish out the chambers and the ports are about as big as they can get. I'm using the LT1 intake port matched 750 cfm Holley

MikeC

Randy, here are the numbers.

Just remember I am a beginner at Desktop dyno

Peak HP 370 HP @5000rpm
Peak Torque 450ft-lbs @3000rpm

I'll send you a screen shot of the graph, The heads I used were low performance, ported, big valve( nothing else matched as well- everything was race oriented). I think thats whats bringing your HP down. If you have flow numbers for your heads, that will help greatly.

Also if you give me your cam mfg, and model number, the cam would be exactly right.

I hope your happy with the engine, I would be.

randy72

The car is driven on the street a lot and I didn't want it to become a bear to drive. $3.00 a gallon gas sucks. I'll send the cam info later today.

Lt1er

I only use 92 unleaded. With cam timing and correct advance curve, mid tens are no problem with iron heads.

randy72

Cam is made by Crane. Part # is CRA-119831.

Lt1er

I looked up your Crane cam and it should be a nice one for a 383.

Fair idle, moderate performance usage, good mid-range HP, mild bracket racing, auto trans w/2500+ converter, 3000-3800 cruise RPM, 9.5 to 10.75 compression ratio advised. Basic RPM 2500-6000

You see the upper 10.75 c/r number it's the max. Crane determined the C/R that could be run with this cam with pump gas with a knowledgable person tunning.

This is my solid flat tappet.

[b]1. PowerMax Mechanical Lifter Camshafts for Non-Emissions Controlled Vehicles


Application Series & Grind Number
Fair idle, moderate performance usage, good mid-range HP, bracket racing, 3400-3800 cruise RPM, 10.0 to 11.5 compression ratio advised. Basic RPM 3000-6500 PowerMax F-278-2
replacing:
CC-278-2

Cam Specifications


Degrees Duration @ .050 Int./Exh. Degrees Advertised Duration Int./Exh. Degree Lobe Separation Open/Close @.050" Cam Lift Int./Exh. Lash Hot Int./Exh. Gross Lift Int./Exh.
238
248
114 10 48
63 5 .022
.022 .480
.500

Do to the .050 cam timing spects it bleed off more pressure so the max C/R is raised to 11.5. That's why my 10.5 works so well with 92 octane. Your roller has other advantages also

MikeC

Putting that exact cam in the engine it goes to

Peak HP 355 HP @5000rpm
Peak Torque 464ft-lbs @3000rpm

I think I have found some flow numbers on a set of 186 heads(original Lt1 heads). I'll post when I put them into the program.

randy72

my head porter/bro. in law "estimates" 245 cfm on the intake and 170 cfm exhaust. I think he's a little optimistic.