Whats up guys, looking for some insight from some FI gurus. Running a Iron 408 right now and CR is estimated around 11.6-11.7 right now with -2cc relief pistons and undecked 62cc PRC 2.5 5.3 heads with a MS3 (114 LSA). Thinking about swapping heads for something in the 72cc range and cam that would be fitting for FI getting my compression down to possibly the high 10's and adding a guess-timated 7-8psi whether it be a tubro or supercharger. Wouldnt be looking for more than that though. This motor only has ~3000 miles on it as of right now and really don't feel like doing a piston swap. Hell this motor is barely broken in from my stand point. This 408 was originally built for a 250 shot but am starting change my mind. Any input would be helpful to make me think about anything that I may be over looking. This is primarily a street car that will see track time from time to time.

Or am I a moron that should just swap the pistons out and dont half *** it??? All opinions are welcome.

Mike

 

I just did a similar build but with 10.5 compression. It made 796 rwhp with 13lbs on e85 threw an auto trans

 

when you do the head swap use some thicker cometic gaskets. wont bring the compression down much but some is better than none.

 

You could always sell the parts you have, if no one will build you an engine with them. I'm not opposed to using used parts.

 

If you are going E85, I'd stick with what you have honestly.

 

stick with what you have. e85 is very easy to work with and very forgiving. my last build was an old school 406 sbc. it was 11:1 compression and had no issues with 16 psi on e85.....with full ignition advance. it did not have the benefit of better combustion chambers like the ls engines do. my camshaft was 238/246-113 and it worked great with twin 72's as well as the blower that was on the car before the turbos.

 

Cam to bleed dynamic compression off.

 

I wonder what route he went 10 years ago when he posted this.