nomorews6

iTrader: (7)

I am looking at a used forged 383 - it has -11cc pistons. It was built for boost, so my questions are:

1) what compression would it be with prc 5.3 2.5r 62cc heads? What should i mill to for best power?

2) what cam should I run? my f13 like cam probably is going to be too small.

3) since i only plan on running n/a or nitrous, does the fact it was built for boost change anything?

4) what size gasket for best power?

thanks in advanced!

orangeapeel

iTrader: (18)

1. Depends on what the pistons are. My guess is your STR is in the 9's. Just a guess though. Those reliefs are not going to hurt you too much as far as DCR goes though.

2.That cam will be pretty mild in that motor. I would go for an MS4 or something of the like.

3.If it was built for boost then the compression is probably lower than you want to be for making N/A power. the only good thing so far about the motor will be it can withstand a load of nitrous and probably just laugh it off. (200-300 shot)

4. Depends on what your pistons are again.


Honestly, if it was built for boost, you better be running some boost through it or it will be a slug for a stroker motor.

nomorews6

iTrader: (7)

Really? I thought milling the heads and/or running a thinner head gasket would solve that problem?

The pistons are -11cc and with 72cc heads make for around 9.5:1 compression

orangeapeel

iTrader: (18)

Yeah. but that is a full point from where you are probably wanting to be You are gonna have a really low Dynamic CR. Not good for power. I wasn't gonna sugar coat it, but you need to know that it will be under powered for what it is. I would sell those pistons and get some for use with nitrous. Basically a -2 to a -4 relief and forged. You could have a stout 11.2:1 motor.

slow trap

iTrader: (22)

i think with an .040 cometic you will be in the 10:8x scr range,give or take alittle.

JakeFusion

iTrader: (7)

Run AFR 225 small bores/ETP 215s/TFS 215 with 58cc chambers. That'll get your SCR up to 11.5:1 with a .040" Cometic assuming the piston is .010" out of the hole.

The F13 will make for a very torquey engine with very good DCR. The F13 on a 112+4 is going to have to much DCR ~ 8.9ish, so I'd probably retard it a bit to get the ICL to a 110. That'll give an 8.75ish DCR, which is the upper limit of 93 octane.

Another option mentioned, the MS4, would be very good. All the heads mentioned either come with or have available a spring that will easily handle the LSK lobe. The DCR with it on a 111+2 is right around 8.5:1 DCR with 11.5:1 SCR. For that cam, you'd be looking at making good torque as well.

nomorews6

iTrader: (7)

thanks for your help everybody, but I guess it sounds like I am getting different information ... is there a calculator for this thing? Why couldn't I just mill my heads to 59cc or something and get a .040 gasket for 11.5 or so compression?

Sigforty

If you want a cam for that engine I suggest calling Futral and getting a custom one. I know my 383 has a cam Allan came up with for my expectations. I told him I wanted something like my F14 in a 346 for my 383. With all the turbo and nitrous setups he is building he has a few grinds that are not on the website.

12Gauge

iTrader: (2)

I run a Comp 244/248 .612 .615 113 on my 383 and it is very liveable. I used to have the F13 and there was a significant difference in power.