Twin engine question
02-01-2019 | 10:28 AM
#1
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From: IL
Twin engine question
So helping out a buddy with an engine build, he’s got a twin engine boat big block GM EFI engines, hurt one Cylinder in the block so he needs to go 30 over, question is has anybody done this before? one engine stock the other engine 30 over, do they run the same or are they out of sync?Is 30 over enough to notice a difference?
02-01-2019 | 12:43 PM
#4
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From: Pasadena, MD
02-01-2019 | 12:54 PM
#5
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From: Northport N.Y.
lol ya that would piss me off to. Only reason I do it to save room if it ever fails again. Did one each block had 2 big pistons and 12 small ones piston people made 12 big ones they had to make 8 more small ones.
02-01-2019 | 04:44 PM
#8
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From: Cheboygan, MI
I bought a boat that sat in storage so long the cylinders rusted so badly the rings wouldn't contact the bores all the way around. I ordered a set of Diamond pistons at 4.565 to clean it up no problem.
02-01-2019 | 07:17 PM
#10
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From: Grand Rapids, MI
I had to pull one of my 550HP 454's last summer and put in a spare Merc 420 I had laying around. There was ~600RPM difference in the engines. A little under 3/4 throttle on the 550HP and the engines were in sync.
You won't notice the difference with 0.030" Put the power steering pump on that engine...
You won't notice the difference with 0.030" Put the power steering pump on that engine...
