Gearing question for 1/8th mile racing

[johnnycarlo]

I've been away for some time but I put a 620HP 572 in my 80 Monte Carlo this summer. Our local drag strip finally opened up for some 1/8th mile racing. I put on real slicks for the first time 28X10.5 Mickey T's. I have 3.55 gears in the Dodge 8.75" diff with a spool. My best time is 6.90@100mph. I have a set of 4.56s brand new in another center section. What gain do you think I'd see by swapping? My best 60 foot has been a non stellar 1.53. I shift it at 5500rpm due to the hydraulic roller cam seems to quit pulling around 5800ish. Thanks for any input.

 

[lilbowtie]

You should be trapping @ 4600RPM right now depending on TC slip. With the 4.56 you should be trapping @ 5750 rpm which sounds like the cam will handle. Have you tried shifting @ 5000 ?? Do you know what RPM your making that power at?

 

[johnnycarlo]

The engine is a 620hp GM crate engine. The only variation is a 1000cfm quick fuel and a 2" HVH carb spacer. I don't have a good dyno curve from one right now.

 

[lilbowtie]

Just noticed - are you spraying it??

 

[johnnycarlo]

Just noticed - are you spraying it??

Not yet I have no roll bar yet.