What seems to be best setup with these heads?...615 or 632? Any particular compression ratio? Cam profiles that seem to work better than others?.What fuels, carb size etc etc.... There's alot of the motors out there now, see them dialed from 4.30s-4.60s in dragsters...just looking from some on hand experiences good or bad with this combination as to why some run better than others. Wanting to build one, just looking for options...thx

i have had a couple of these 615,s great motors by sunset. currently have a zero pass new one with dyno only time if interested.


http://www.sunsetperformanceen...=PRO%20LITE%20SERIES

Call PAR.

LS firing cam swap…

I've been running the SR20 combination since 2015. Just about as long as anyone.

I'd certainly go with the 18 degree stuff if building new. If in a dragster I wouldn't go over 63x on CID simply to keep the torque down.

Cam profiles aren't as big of deal as you think unless you get over 1" which most builders don't like to do due to longevity.

Most 4.3x stuff you see are 648 or 65x. or in great air. 632 run about a tenth quicker than a 615 and most run in the 4.4x range in good air and 4.5x in summer air.

Carbs are a pretty big deal as most SR20 stuff seem to have a different signal and a lot of builders struggle tuning for that IMO.

Converters and gearing are equally important if you wanna run fast as these engines like RPM.

I have both used 615's listed for $27k which is about $10k less than a new Aluminum Block engine.

Best of luck whichever direction you decide to go.

SL...

quote:

Originally posted by DragRaceResults:
I've been running the SR20 combination since 2015. Just about as long as anyone.

I'd certainly go with the 18 degree stuff if building new. If in a dragster I wouldn't go over 63x on CID simply to keep the torque down.


SL...

I am a small block guy so can I ask what is reasoning for 18 degree over 20 degree?

Curly the new 18 degree is making considerably more power. Close to 100 on a big engine. Similar to an 18 degree or 16 degree SBC compared to a 23 degree. Basically runner angle into the chamber along with a smaller chamber.