Need opinions: adding top-end to 8# ATI + stock bottom end

Rybar · 01-29-2003, 02:05 PM

Hey guys, I need your opinions.

I have my '94 Trans Am which is running the parts listed in my sig. It basically has a stock engine (save for 52 mm TB and 1.6 RR) and an 8 PSI ATI P600B kit with front mount 3-core intercooler. I am running stock tuning and stock injectors with the ATI kit and have had the kit on the car for about 5 years. Mind you it is not my daily driver. The car was dynoed at 415 rwhp (before the 12-bolt) and has run a best trap speed of almost 115 mph in the 1/4.

I have a pair of CNC ported LT1 heads, fully assembled with larger valves, new valves springs etc. I am also going to get a super deal on a cc305 cam, CSI water pump, cloyes timimg chain and '95 timing cover. I am also putting new RK Sport 1-3/4" shorty headers and a Borla Cat Back on the car (replacing my old exhaust set-up)

I realize most of you will say my stock LT1 will blow up, and so on. I fully know this, and will build a budget 355 with SRP 9.5:1 pistons and stock crank/rods with full ARP fasteners. I do not have the budget for a big 4340 fully forged bottom end, so I will not be planning a build like that.

Question 1: Would you guys recommend doing this? Would it jeopordize blowing my bottom end any more than the setup I have now?

Question 2: What kind of tuning would I need done if I add this top-end setup to my current setup? How do you tune the computer with the FMU?

Thanks in advance,
Ryan

TimbrSS · 01-29-2003, 03:24 PM

Sounds like you got the right idea. What's your rwhp expectations? What octane gas are you giong to be running?

I'm guessing 500-550rwhp? I'd try to upgrade your rods while your at it.

Have your heads been milled at all to raise compression? Take that into account when ordering pistons. I'd consider dropping down to 9:1 compression, depending on what gas you're running, how much boost you're planning.

I'd ditch the FMU, go with walboro 340 intank, 50# injectors, LT1 edit. Get a good dyno tune.

I wouldn't just put the new top end on the stock bottom end. It's alot of work/tuning, just to have to do it again when the bottom does give out.

jimbo95Z28 · 01-30-2003, 11:09 PM

I have been thinking about doing the same thing except I already have a hotcam, and I have the heads sitting at my house. They are 64 cc combustion chambers, and I have slightly better hypereutectic pistons with valve reliefs(.030 over), and teflon coated skirts, balanced stock rods, and a balanced crank with new bolts(don't think that they are ARP) I really would like to put a P1sc with 8psi on to that motor, and I also know that with those heads that weuld be a pressure drop, so i would probably only see 6 PSI or so. do you all think that it would be that deadly to put a blower on there? My compression would be quite a bit lower than stock so I shouldn't have a big problem with detonation. Please let me know what you think.