I'm assembling a 4g64 with a BC stroker kit, evo 4 head (basically the same as a 5-6-7-8) and GSC S2 CAMS. When I bought the CAMS, the site said it could used with stock springs for stock Rev rang but needs upgrading springs to rev higher. Since there is little to no info on a stroked 4G64, I have no idea how high I can rev this thing.

Should I upgrade the springs (and retainers)? How high can I rev this combo? What else should I upgrade in the engine?

 

There is info on how high you can rev the 4g64 motor. If it is a long rod kit you can do 9000-9500 ish if it is a standard kit up to 8500 or so. If I were you I would being the stock rev limit is only 7200 rpms. If your going to wind out that motor you mine as well upgrade.

 

Its an out of production BC stroker kit with a 106mm stroked crank with rods and pistons setup up for the standard 86.5mm bore and 8.5 compression for the 4g64. I'm not sure if this is long rod, but I remember reading that it was in some thread here. The GSC R2 didn't exist when the S2 were bought. The S2 seem to be cams the respond at higher revs. Hence my interest in how high can this setup be revved, but if not more than stock(7600 RPM), should I stay with the stock springs?

 

Ok well in that case then I would get springs. I have s2 cams and they are great, I rev all the way to 9500 if I want to with my current springs. If it were me id upgrade springs just for added insurance and not having a chance to float a valve.

 

Suggestions, brand, model, etc?

 

Well I am bias being I work for PSI springs lol I use those but we don't make a 4g spring. So with that said I would say use my competitors springs. Kiggly springs are probably the best springs ( other then ours lol) for our cars. I would use his in a heart beat. Hands down best option for the car.