how much boost???
#1
Thread Starter
Registered

Joined: May 2011
Posts: 576
Likes: 1
From: Varna, IL
Motors started as hp500s. Standard stroke, bored for 509". Inverted dome for 7.6:1 static compression. Stock heads. 525 efi cams, H-beam rods, main studs, arp head bolts, 420 mega blowers with super chillers. Pullies i have are 17% overdrive. What would i expect out of this combination or do a look for bigger upper pullies?
#2
Registered

Joined: Jul 2004
Posts: 11,332
Likes: 73
From: chicago
I would probably start with the 17% overdrive and see where it puts you. What size pulleys do you have now for top and bottom?
With 7.6:1, GM rect port heads, 420 blower, your real close to what the merc 600SC was, except for cam. I wouldn't hesitate to run 8psi with the intercooler, maybe more. DMOORE on here, had a stock 600SC, added a chiller, cranked the boost to 10psi. Engines been running that way for a looooong time.
With 7.6:1, GM rect port heads, 420 blower, your real close to what the merc 600SC was, except for cam. I wouldn't hesitate to run 8psi with the intercooler, maybe more. DMOORE on here, had a stock 600SC, added a chiller, cranked the boost to 10psi. Engines been running that way for a looooong time.
#6
Registered

Joined: Oct 2007
Posts: 8,439
Likes: 93
From: yorkville,il
a long time ago i had a similar setup but no inncrcooler and i ran 8 lbs boost,blower was a bds 8.71 it is slightly bigger than your 420,it was in a 27 ft cig copy.i ran it hard for four years,then put it in a 18 ft sanger and beat it for 2 more years then sold it.never had a problem.
#7
Registered

Joined: Jul 2004
Posts: 11,332
Likes: 73
From: chicago
a long time ago i had a similar setup but no inncrcooler and i ran 8 lbs boost,blower was a bds 8.71 it is slightly bigger than your 420,it was in a 27 ft cig copy.i ran it hard for four years,then put it in a 18 ft sanger and beat it for 2 more years then sold it.never had a problem.
#9
Registered
Joined: Oct 2010
Posts: 1,621
Likes: 402
From: Cheboygan, MI
a long time ago i had a similar setup but no inncrcooler and i ran 8 lbs boost,blower was a bds 8.71 it is slightly bigger than your 420,it was in a 27 ft cig copy.i ran it hard for four years,then put it in a 18 ft sanger and beat it for 2 more years then sold it.never had a problem.
#10
Thread Starter
Registered

Joined: May 2011
Posts: 576
Likes: 1
From: Varna, IL
I ended up milling my tall decks down. Plenty of meat left them.
And i don't remember the sizes off hand but I've got it written down somewhere. It came out to 17.1something.
Glad to hear the positively on the reliability aspect of my build. That's my main goal!
And i don't remember the sizes off hand but I've got it written down somewhere. It came out to 17.1something.
Glad to hear the positively on the reliability aspect of my build. That's my main goal!


