lt1HULK

I just got through building my fully forged 383 motor. The specifications are as follows:

383
6" rods
Approximately 9.5:1 Compression
Stage II Ported Heads
P & P Intake Manifold
1.6 RRs
Comp Cam "502"
52mm Throttle Body
Grantelli MAFS
Moroso CAI
RK Sport Headers
!Cat
!EGR
!AIR
SLP Loudmouth
MSD 6AL Ignition System
150 Shot of Nitrous
4.10 Grear
pcmforless programming
lots of small mods

What do you guys/gals think I should be running N/A and spraying in the quarter and the eight. Also, what sort of HP and TQ numbers should I be putting out? Thanks,

Jason

96z

Depending of flow numbers, 370rwhp or so NA.

lt1HULK

Why so low? I was under the impression that with this setup I should be expecting low to mid 400s for both hp and tq to the wheels.

Also, I forgot to say that I'm using 30# injectors. The nitrous kit is the NOS dry kit if it makes any difference.

What are the average numbers for 383s built on this site? Would mine be about average or below?

~Jason

Seal

way more than 370 man... 370 is like a LT4 kit... almost :P

i'd say low mid 400 at the wheels NA

Perry93TransAm

I can see 400 at the flywheel but not at the wheels. It will make gobs of torque , well over 400 at the wheels.

Rival

Give us the flow numbers of the heads. A custom grind cam would work best with your heads because the cam would be ground for the heads. The 502 isn't the biggest cam either. I would guess 390/420 hp/tq. You would benefit from long tube headers and a dyno tune.

CMoney

Why only 9.5:1 compression?

96z

Heres a short list...

1. If your heads dont flow well across the board and atleast 270-275 at peak.
2. Non optimal headers, rksports arent the best.
3. Compression potentially 2 points too low for best power
4. Considerably undersized to most cam for 383
5. Mail order tune
6. 4.10 gears will lower the numbers on the dyno...

gb95zconv

I would bump the compression to 11:1 or so if you just plan to run NA with a shot of juice. IMO the 502 is way too small.....do at least a 503 or 305.

I think 350-370rwhp is where you will land with your planned compression and the 502.

lt1HULK

The reason I went with 9.5 to 1 compression was because:
1. I wanted to be able to spray a little more
2. I liked the idea of being able to run 87 octane when I want

This was the solution that suited what I wanted out of the car. This car is still my daily driver and I don't want to go all out with it. I wanted it faster, and to have more torque, all the time, but I didn't want to have to mess with achy or fuel mixing that usually comes with upping the compression at or above 11:1 on our cars. Before anybody gets started on this, I know that there are cars out there that run higher compression that don't need special fuel, but I am talking in general. By lowering the compression, I allow myself to have more power when I want it by being able to spray more. That is also why I chosed to use 4340 forged steel on my motor internals.

I don't know what the flow numbers are on my heads, but I do know that they were ported by a VERY reputable machine shop in the area. The shop does alot of high performance professional drag cars so they know what they are doing. The impression that the machine shop gave me was the port job they gave me was the best that could be done (within reason) on stock head castings.

As far as the cam in concerned, the car is a daily driver like I stated before. I don't want a really choppy ride just cruising down the street, but I did want power increase. I called comp cams and told them what I was doing with the car and they recommeneded the 502. So far, the cam seems to be working out fine. Nice coppy idle, but not too much. If I want to go more aggressive I have the 306 sitting in my closet at home.

The RK sport headers that I have on my car are not the best, BUT they seem to come close. They had the aspects that I wanted in headers and they were a good bit cheaper than the long tubes. They are ceramic coated and have 1 3/4" runners. They probably don't flow as well as the long tubes, but they are close, if not, the next best thing in my opinion.

lt1HULK

Oh yea, the mail order tune is just going to be used as a baseline. I am planning on using lt1_edit once I have everything on the car squared away and running right.

jonaddis84

Im thinkin the 30# injectors are gonna be a little small for that setup. They are right on for the motor NA, but with a dry 150 shot you are gonna be pushin it real real close. You would need 30s just to run the 383 basically. If you had a wet system it wouldnt be a problem obviously. Might want to look into that before you start sprayin it.

lt1HULK

I was thinking the same thing about the 30# injectors. To fix the problem I was debating whether to convert to a wet plate kit. Sound reasonable?

QCKZ28

id would say 350rwhp/380rwtq, due to the small cam and low compression.
jesse

jonaddis84

Yeah, it would definitely be easier and cheaper prolly. All you need is another solenoid and a new nozzle i believe, and some more wiring. But 36 or larger injectors go wayyyyy up in price, almost double i think. Plus a wet kit is more effective, less tuning required.