dvickrey

I am currently looking for a C3 to add to what I hope will one day be a collection of 6 generations of Vettes. I am looking for a 68-72, preferably big block car. One car offered here locally is a 72 454 equipped car. I know that these cars were rated at 270 HP... and I believe the quoted figure is SAE net rather than gross. Can someone confirm that for me? (If I am correct, that would put the car at about 330-360 SAE gross - a little down from the earlier years during which power was a bit higer when compared on an apples-to-apples, i.e., SAE gross, basis.)

I am also interested in learning about engine changes that were made between 1970 and 1972 (presumably most were made for emissions compliance). In this regard, are there any relatively easy, reversible modifications that can be made to restore HP to 1970-71 levels? For example, removing smog equipment, running an earlier model carb, etc.

Thanks in advance for your help!


[Modified by dvickrey, 6:45 PM 3/6/2003]


[Modified by dvickrey, 6:48 PM 3/6/2003]

page62

Increasing HP is a piece of cake -- don't worry about it. Just go and find the cleanest, most mechanically sound car you can find (and want). Then come back here and we'll give you at least 50 different suggestions to add some ponies.

gerry72

The LS5 for 1971 was rated at 365hp (the LS6 was also available in this year only and rated at 425hp). It is the indentical engine for '72 except for the difference between the gross (for '71) and the net (for '72) rating. Normal modifications will make a difference (headers, cam, intake,...). Don't bother altering the factory smog equipment if you happen to find a car with all of it on. It didn't have as much of an affect on horsepower as the tales would have you believe and much of it is beneficial to engine efficiency.

73 LS-4

In 72 everything was changed over to net ratings, 270 is approximately 330 gross. 71 was 365 gross hp, which I believe was 285 net for an LS-5, so your not talking a big power difference between 71 and 72 or 73 (275 net) to 74 (270 net) for that matter. 70 there was a difference though and that was through compression, 70 was the last year for high compression and the reason for the 390 gross rating. If you want to make more power on a Rat chevy the simplest and most cost effective change is a set of headers and recurving the distributor will easily put you ahead of the stock 71 numbers with a 72.

:cheers:
Pat Kunz