[BILL BOWMAN1]

If building a roots blower motor from scratch, would you start with 72 or 87 ccs, or does it matter? Would be a pump gas 535, looking to build 900+ hp.
Thanks

[johnta1]

With a blower, one would want low cr, so the bigger chamber is better.

[Curious George]

Originally Posted by johnta1

With a blower, one would want low cr, so the bigger chamber is better.

Agreed, especially with the big cubic inches.

[BILL BOWMAN1]

Thanks guy. Now I just need about, 10,000 hours of overtime!😀

[mysticmissle]

i think 72cc e heads flow more then 87 cc e heads for example. if theyre ported its still a consideration. if you havent ordered pistons or heads you have options. especially w a 535 youre going to need dished piston with either size head.
i am building a pump gas 505 to eventually turbo on e85 and race gas. i have 87cc e heads and about 10:1 or hopefully slightly less with the piston a skosh in the hole.
my friends ls stuff is turboed on e85 in the high 12-13:1 compression

[BILL BOWMAN1]

I have wide ports right now, I don’t want to build a custom intake, and want to get away from the offset roller lifters.

[blueghoast]

I went with a 400+60 and big cc-455 heads Comp is 7:89"1
It's pump gas friendly and made around 600-hp with a small
flat-tappet cam that Scott Brown profiled for me, very simualar
to a RAIV cam with a 8-71 blower, very street able and
pump gas 3"42 gear and a tight converter from butler.

GT

[charlie66]

Under 9:1 is best . I prefer the smaller chamber with dish tops to get it there ... Being its a lager cubic inch it might be a challenge thou.. I have 8:4 and its nice an easy to tune.. The higher you go the smaller the tuning window..

[blueghoast]

I upgraded the camshaft now I just have to get the car finished that
this blower motor is for. I'm also waiting on a adapter to put on a
wenzler intake (shorten of coarse) seen it done on engine masters
with a big block chevy and made a 100HP more with back-back runs.
I figure with both upgrades hope to see 700HP possibly.

GT