Hello, I am very new to the LT1 engine, having never worked on one other than putting on some aftermarket intake pipes, and driving a few T/As around from time to time. I am however above-averagely mechanically inclined, I've built a dodge stealth that still retains a stock 3.0L engine that's very very fast. However recently I was bitten by the V8 bug and i've decided to invest in a rather complicated project.

My car is a 1985 RX7. The engine is an LT1 with rod knock out of a 94 Z28 A4. I am building the car to compete on a road course (road racing suspension, wide body, T56 transmission) however I'm hoping that with a spring change, shock adjustment, and a large dose of N2O it will be a 9 second beast.

The car itself will be very light, completely stripped, fiberglass widebody, 12 point chromoly cage, bucket seats and some fans under the dash, that's about it. I would like it to be a barely liveable daily driver, while mostly being a track car, it will be registered and insured as a street car. I'm going to put a Ford () 8.8 in the rear end and build it, however it will have a good LSD, no locker here.

The motor is going to be a 383ci LT1. I've got an Eagle forged crank, H-beam rods and SRP pistons. The block is going to have splayed mains put in. It will be getting a 200 shot at the strip, and maybe occasionally on the street. I've found some very nice NX and NOS setups, it will not be a playschool setup either, this thing will have all the safety equipment available. For the ignition on it I'm trying to find information on converting to the DIS-4 from the Northstar, as I'm sure I'll be requiring powerful spark on the high end for extended periods of time. My questions ultimately come down to my head and cam options.

My goal for the motor is about 500-550 crank horsepower N/A on pump gas. I've got some friends with the desktop dynos and they're saying that Crower's largest nitrous cam is too small for the power I'm looking for. Does anyone have any suggestions? I would like idle to not be over 1700RPM, and redline to be under 7000RPM, because I want streetability to exist (somewhat ) I'm hoping for something that doesn't have much over 245/260 duration, and over .550" lift.

In addition to this I'm somewhat hungup on the heads question. I've been looking around and it seems my best options are the AFR 210LT4 or 220 LT4 heads, however on their website they say I'll need an LT4 intake manifold. Is this true, or is this simply for optimal flow. also these heads will be seeing extensive high RPM on the roadcourses. Alternately, does anyone have experience with other company's heads that are competitive, being used in this type of atmosphere?? Ai, LPE, etc...

Thanks for your help, I've been using the search button but as the forum is filled with some on topic some off topic information, I haven't quite learned the best words to use in the searches to make them efficient. Also my apologies if this is the wrong forum for this, I found it crossed into many categories, including Engine Tech, N2O, and Road Racing, so I thought I'd post it here.

thanks for your time, David

 

well I found out I do have to use an LT4 manifold, no biggie. Is the Holley LT4 manifold any better than the Accel manifold any better than the Stock one from GM parts direct? I still can't find any good info on a cam.

 

For info on using the Northstar ignition, while retaining the optical sensor data from the Optispark distributor, and full sequential injection:

http://delteq.com/default.htm

I think you're overestimating the the cam requirements. I'm making 500 flywheel with a mild 230/242 114LSA, 800 rpm idle speed. It was selected to pass NJ rolling emissions. You might be overestimating the head requirements as well.

You might want to look for posts by "jimlab".... he has an LT1 stroker making about 650 flywheel HP, that is headed for an RX-7 chassis. He has worked out a lot of the details on the chassis and drivetrain issues. The engine is a masterpiece.