darren s

iTrader: (1)

I have a 90 mustang with a stock lq9, polluter cam, vic jr intake, 850 carb, longtube headers, and a glide w/ a 5k stall that occasionally gets hit with a 150-250 shot of nitrous. I'm shifting it at 7k but would like to be able to pull it up to 7500 on the spray in the 1/4mi if needed. I've only sprayed a 150 shot so far and it went 6.2@111 and 9.8@137. It usually runs 6.8@100 and 10.6@126 NA. I want to make it a little more durable for nitrous use so I at least plan to upgrade the rods and pistons. While I have the motor apart I'd like to warm it up a little bit too so here are my questions. Keep in mind I'm trying to keep costs down so I'm really looking for the most bang for the buck. I'll be racing 7.0index classes so the car is already quick enough NA but if I could get to 6.0 NA I'd run that, or if it ends up in the lower 6's I could always slow it down some.

1. Should I keep the stock crank and just upgrade the rods/pistons, bore it .030 and put the crank money towards better heads or build a 408? Would the 408 like the RPM I am wanting to turn?

2. Should I have the 317 heads ported and milled, use another option in the cathedral port family, or switch to ls3 style heads (which would mean I'd have to buy a new intake.)

3. What is reccommended to safely turn these motors to 7500? Oil mods, valvetrain, etc? I've turned it 7200 a few times on a shift and so far all is good on the stocker. I have a moroso pan on it. I'm guessing I need to upgrade the rocker trunions while it's apart?

4. Is the cam I have ok for all of the above combos or would it need to be changed out? I don't remember the exact specs but its low .24x's @50 in/ex and just over .600 lift on a 112 lsa. I would imagine it may be okay at 370ci but might peak sooner on the 408.

baronsmith98

iTrader: (2)

I myself have a 370 with 317s milled .020" 10.5:1 compression and its real rev happy. I hear the square port heads like high rpm even more. I wanted to do a 408 but that extra money for the crank was out of the question at the time. Spinning that high i would definitely get some good lifters and do the trunion upgrade. As far as cam call Martin@tick performance hes great

darren s

iTrader: (1)

Thanks for the input. I'm shifting my cam only lq9 at 7k now and it feels like it could take more!

darren s

iTrader: (1)

Well after finding out that Advanced Induction is right in my back yard I think I'm going to send them my 317's for their 232cc program. Now the decision is 408 or 370. With the 370 I'd probably have the heads milled some, but with the 408 and flat top pistons the compression ratio should be about right for pump gas on the stock chamber. Anyone see any problems with either route. If the 408 is not going to make much more power given the capabilitie of the ported 317's at 7500rpm then it would not make much sense to spend the money. Would a set of dome pistons from wiseco be an option on the 370 combo knowing that it will be sprayed? Opinions?? Thanks again.

VLS1

Cool ride Darren, maybe share it over on the carb LSX section and you'll find more response there for sure.

https://ls1tech.com/forums/carbureted-lsx-forum-172/