SLR Advice

Hi Guys, I'm looking for some starting line ratio advice on a build likely hitting the track in spring. It's a Brand X, but I'm on this site almost daily and I know there are several serious racers here and I value the input greatly. Scoop on the car:

2600lbs/4 link
31" tire/1.76 first gear glide/5.14 gear
775-800hp/3.625 stroke

This car will be footbrake only, no transbrake in the future. The intent is to break into the high 8's NA. If my math is right, I'm coming up with a 9.05 ratio SLR as it sits now. Might be a little light, but with this high rpm combo it will be very dependent on a great converter to get it there. If I'm way off, please share.

Thanks!

I would run it as it is and try to be able to data log at least driveshaft speed vs RPM and go from there.

You won't be too steep on SLR, unless you over rev it ( too much rear gear) on an 1/8 mile track, IMHO. If you race a delaybox class, you can launch at a lower rpm if need be. I have had good consistancy with 11.17 slr, much more than recomended by most, by launching at 3900 on a converter that flashes to 6200, running 8.60 1/4 mile with 550 cubes.

We run SLR's in the 12's with the red car on a 29.5x10.5 tire(not W)with no issues running 7's. Dont get caught up in "ideal" numbers every combo is different. Might have to work on the car a bit to make it work but if you have an ET goal you are gonna have to work to get there anyway.

I also run 8's with a 3600lb 64 Plymouth NA and my SLR is 10.4 and still on the 29.5x10.5 tire. Its not rocket sceince.

Thanks for the replies Guys. I think we just need to go out and thrash it to see what it likes and go from there. The rear gear was picked to match up where we thought we'd be at RPM/trap speed-wise. If we do need more, powerglide gears aren't hard to find.

I suspect it will like more ratio in the glide, as that short stroke can use it.

I am guessing the same.

I would look into using the 1:80 low gear set and then find out what RPM your motor wants to be shifted at with that ratio

Yeah, that's the direction I'm going. The higher numerical ratios above 1.80 appear to be limited to what kind of power they can take. This engine will have a shift point between 8750-9k.