1975 Vette Owners!

[kridgley]

Hey, I just got my 75 vette ... i was wondering ...since this is pretty a sh***y engine compared to the other vette models ... what all did you do to tweek to upgrades your 75's???
so far i swapped carbs (rochester 4bbl to a Holly 4bbl)
intake ... to an edlebrock performer
and lastly ... did away with the two Y's , to two straight pipes and mufflers....

kev

 

[brusso]

About all of done with mine so far has been get rid of that exhaust mess and go with duels with flowmaster "40's", push the timing up to about 12-13 BTDC, and adjust the stock Roch carb for best idle and 4barrel operation. I had too many other $$$$ things broke to do anything else.

 

[mike weyman]

the performer rpm is the baby, the performer is barely better than the stock intake(if it is better).
when i got my 75 i couldn't believe my old neon could (and would) eat it alive.
i started with a 460 lift cam,had the heads done (port polish gasket matched).holley 680 d.p. carb. weiand excellerator intake,th350 tranny, with shift kit and 2400stall converter.the only thing i would like to add is a new rearend. as it is it will run slightly over 300 h.p.mike

 

[rpounds]

You've got to get the compression up before anything else will do much good. The stock 882 castings with 76cc combustion chambers, coupled with the dished pistons yield an anemic 8.5:1 theoretical static compression. Going to a better breathing head with smaller chambers (64cc specifically) will boost the compression by about one point. That alone will give you a significant performance boost. Now that you have decent compression, a cam swap would open things up even further. Remember that a cam with any significant overlap lowers the static compression and the engine will become a real dog in the lower RPM range. Therefore, you have to determine where you would like the engine to make the most power. If you want it in the 500-4000 range, select a cam that puts the torque curve down low. If you want to add a stall converter (in the case of an automatic trans), then you can get away with a bigger cam with some overlap, which will equal power in a higer RPM range.

I have a '75 too and was very disappointed the first time I turned the key and smashed the loud pedal. After some inexpensive tweaks, it runs like a vette should. I found a pair of camel humps with 64cc chambers (actually a little less because the heads had been milled) for a very modest price to boost the compression and added an appropriate cam for my overall setup. When I bought the car, it wouldn't burp the tires. Now it will burn them. This setup will do for now . . . although at some point in the future, I would like to find a good block on which to build a stroker, which I personally think is the hot setup for these cars, especially with how heavy the cars are.

I hope some of this helps.

Ron

 

[norvalwilhelm]

I replaced the small block with a big block, added a 8-71 blower with 15% overdrive for 12 pounds of boost, a pair of 850 double pumpers, a 5 speed overdrive Tremec, coilovers all around and tons of work in the steering, most of it taken from Grand national stock cars.
It did make a big difference

 

[brusso]

I replaced the small block with a big block, added a 8-71 blower with 15% overdrive for 12 pounds of boost, a pair of 850 double pumpers, a 5 speed overdrive Tremec, coilovers all around and tons of work in the steering, most of it taken from Grand national stock cars.
It did make a big difference

Yea, I guess.