This weekend I'm going to finish assembling my ZZ4 that my generous ex roommate left in my garage for me to have for free.
:lala:

Next weekend it appears that the L98 is coming out like it or not.


For those who have done the swap and kept the TPI is there anything that I need to be forwarned about prior to this turning into a year long project?

Thanks in advance.

 

The zz4 has aluminum Vette L98 heads, which have the older style pre-86 intake bolt pattern. All your going to need to do is elongate the 2 center holes on each side of your TPI intake manifold, as you have an 89. Other than that it should be a direct swap... aside from PROM tuning.

good luck!

 

Why will he need prom tuning?

 

The ZZ4 has a different cam, which has a different powerband, which will require custom spark and fuel tables. The car should run fine with the factory prom, but you wont get the most out of it untill its properly tuned.

 

Be prepared to loose 50hp to the TPI. Unless you've upgraded it. Prom tuning. as stated before, is not required but highly recommended.

 

Well My 91 went 13.11 with the stock chip with the zz3/4 cam. He doesnt have to get a prom burned it should still run just fine. I would like to see a before and after prom burn and see how much difference it would really make.

 

What other mods did you have at the time to yeild a 13.11?

 

160 stat, 50 psi fuel pressure (put a dime in the regulator) 12 degress timing, air foil, marsh under drive pulleys, 3.42 gears, ground the plenum behind the throttle body, throttle body coolant bypass, home made ram air from behind fog lights, trans pac and slicks.

 

The stock chip will take just fine to the swap as he is running a MAF.

 

I Have to agree that it would run fine with the stock prom. It seems since the prom burning board opened up everyone is getting a little wild with the suggestions on making or getting custom proms.
Granted it will increase performance if properly tuned but with a ZZ4 stock TPI combination like this one, How much more performance can really be made, even with an expert tuner?
I would be very interested to see if anyone has actual dyno #s to back their gains with custom proms and this particular set up.

 

Do you remember what kinda 60' you were running? Just curious, I'm very impressed w/ your times.

 

I had a 1.73 60ft on that pass.