My current setup is a completely forged with cam 355 LT1 with 8lb ATI procharger with stock intank pump and ATI inline pump running through 42lb injectors. This setup is making 408RWHP. I am looking to upgrade to 12lb of boost with the Walbro 255 intank pump and no inline pump. I am looking to make between 5-600 RWHP, what injectors would you all recommend or are currently using in a setup similar to this? Would 42lb injectors be enough?

Thanks,
Matt

I asked this question already if you do a search you will come up with at least a couple threads. Consensus is 50# will be cutting it very close but for anything close to 600 rwhp you will need 72# no ifs ands or buts.

Just for comparison with my s-trim on a 385 making 5lbs boost my 50# injectors @ 6000 rpm are at 96% in 3rd gear. I am upgrading mine to 72's or more even if I don't up my boost to 10lbs.

I'm no pro, but has your car ever been tuned?

steve10358, If your asking about my car for now it has a tune from Bryan at PCMflorless and is running good with 0 timing pulled and no KR, but running a little rich. I suspect it is a pretty safe tune because I was getting more HP before I had Bryan send me the tune and As soon as I can I'm going to get it on a wideband O2 dyno.

My set up just made 525 rwhp with 42#SVO injectors, and a Super FMU, see 58 psi of fuel pressure at 6,100 rpm at 8 psi of boost.

The MAF hit 471 gms/sec (maxed out) at 5,400 rpm, so watch out for that sort of thing, you may have to adjust the PE curve to help out the fuel situation.

My air/fuel ratio was 12:1

Hope this helps

LWM

Hey bud- I'd be willing to bet you could prolly get another 75 horse out of that thing with someone that knows how to program. I've seen the difference between PCM4less and custom tuning. I'm lucky I have capable friends with a wide band.

I can't believe PCM4less does what they do, it's actually quite horrid!

steve10358 , I have heard both good & bad about PCM4less, But for $50 I thought I would give it a try so you probably get what you pay for. My problem is the closest Wideband O2 dyno is 250 miles from here so I've been using Tunercat & Datamaster till I get a few more miles on the motor and get to the Dyno.

Im probably am goin to only make around 520 RWHP or so but I want to buy an injector that I will not have to change if I do some other mods, If I got 72's and only made around 520 is it possible to have too much injector? or would tuning fix that problem?

I have a mild 355 with 8# boost(plus hard 4" intake) and am making 500 rwhp in an auto. I am using the stock intank, ATI inline, 42# SVOs and a voltblaster. My injectors are maxed as well as the MAF early in the RPM range as was mentioned earlier.

The best advice is learn to tune yourself and get some wideband dyno time.

Why do you say that about PCMforless? If you take the time to get a program, log runs, do some research and revise the program the mail order is not THAT bad. I mean compared to a wideband o2, well you can't really compare that... but honestly, I have PCMforless and my runs VERY strong. 0 knock with barely any timing pulled on the BTM. BLM's are constant 128. I have gotten 270 miles to the tank and average around 250... I'd said that's pretty damn good for a mail order tune. We'll see how he does with this cam I'm finishing up this weekend.