Quote:
Originally Posted by EZ Nova
Now back to these 430 ZL1's. Like I said, I don't see a 430 cresting 700Hp back in the early 70's?
Grumpy's '68 BEST pass for the 1970 season according to Draglist times was 9.845 and @ 3010 IF he was only 430 inches would have been 623Hp. YET most go by MPH when looking at Hp at the track. The BEST that car went in 1970 was 138.03 and @ 3010 would have been 609.9Hp.
Now the thing is, It doesn't look from all accounts the Grumpy ran the CA 430 ZL1? I not only have the magazine from July of 1970 where Grumpy built the 70 with a GM 430 inch RAT motor. So the size isn't in dispute, BUT it does say he used the GM 427 crank.
Therefore he would have the normal "052" 4.250 block ZL1 as the engine wouldn't have been 430 with the 3.75 stroke crank and 4.440 bore, more like 465 inch. There is also mentioned out there that for match racing, Grumpy would use a mountain motor and take ALL the weight out of the car. The stories I've heard was a 4.44 block and 4" 454 crank for the old 495 inch but the weight was out, so who know what that motor would have made. I seem to doubt that even Grumpy's 495 IN 1970 made 700Hp? His best match race time was 9.40's but was there 100lbs out or 200 lbs out. It wasn't 3010 legal weight to make the 700Hp.
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The 430 cu.in. CanAM engine had a lot more going for it than the ZL-1 combo. The CanAm block with the siamesed cylinder walls made for a more rigid block by tying together all the bores, less block shift at high rpm. Also the 4.440 cylinder bores had the effect of unshrouding the valves just by virtue of the larger diameter bores. The short throw crankshaft of 3.47 stroke (think 350 sbc size crank) allowed a better rod length/stroke ratio of 1.768 versus a rod length/stroke ratio of 1.631 for the 3.76 stroke crank, which places the piston at the top dead center for a longer period of time than a longer stroke AND results in less side loading of the cylinder walls by the pistons to ensure cylinder block stability. Also by the shorter stroke, one can rev the motor higher as it would be in a Pro Stock car. NHRA had a 7 lb per cubic inch rule not hp rule. So theoretically, the car would weigh very little between the 427 smaller bore/long stroke and the 430 larger bore/shorter stroke combo ( 21 lbs). This reasoning was the main push behind the 430 CanAM engine combo in Pro Stock. Jenkins used the same reasoning with the '72 Vega. It was true that the 350 sbc made just a little more horsepower than the 331 sbc, but the additional weight (@ 140 lbs) it had to carry would make the combo less viable, competition-wise. I think the heads for the 430 CanAm motor used 2.30 intake valves also.