I was wondering whether it was actually worth it or not. Are the "425 HP" statements accurate? I have the LT-4 heads with GMPP 1.6 RRs on my 94 TA now, but I didn't get to do anything with them before I put them on. Otherwise stock except for the built trans, what kind of gains should I get from them ?

 

The advertised HP is achievable as long as you have headers and tuning.

1.6 rockers and heads are nice, but you will also need a bigger cam to take full avantage of them. My guess is that you're around 300-315 RWHP right now, depending on what else you have.

 

You will never get the 425hp mark with the conversion kit cause the comp they used for tuning coast several thousands of dollars.

 

I'd have to disagree. I've tuned several hotcam cars that went over the 340 RWHP mark, on stock LT1 heads. 425 flywheel HP equals ~ 360 RWHP considering a drivetrain loss factor of 15% for a manual transmission. The heads should be good for at least 25 RWHP which would make it possible to reach that mark even with mid-length or possibly shorty headers.

 

How long does it take to do a cam swap, with shop use and air tools ? I've never done one, but I'm a mechanic. I coulda done the head swap in a day if I'd had the parts. Also, has anyone had an EGR problem after the head swap? When I hook up the vacuum line, it idles very rough.

 

If you got a shop and the skills you should be able to do it in about a day. However I would make sure you have a free weekend to do it on just in case.