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-   -   Cost of 454 to 540 upgrade? (https://www.offshoreonly.com/forums/general-q/178786-cost-454-540-upgrade.html)

Chris Sunkin 02-01-2008 11:55 AM

There's one avenue that seems all but forgotten... the 427 truck block. It's a tall deck but it's also super-heavy. The bores aren't siamesed but they're really thick and the webs too. I've yet to see one that won't take a .100 overbore. Last one's I bought were $300 each on racingjunk.com

jeff1000man 02-01-2008 12:00 PM


Originally Posted by Chris Sunkin (Post 2428939)
There's one avenue that seems all but forgotten... the 427 truck block. It's a tall deck but it's also super-heavy. The bores aren't siamesed but they're really thick and the webs too. I've yet to see one that won't take a .100 overbore. Last one's I bought were $300 each on racingjunk.com

I have one of those blocks. Havn't been able to come up with a good solution to build anything worthwhile out of it.

From what I have read, you can't get a big enough bore to make it worth the effort..

You can stud a 2 bolt block and it will take a 550 HP engine. A 4 bolt would be better, but you gotta use those 2 bolts some times.

Chris Sunkin 02-01-2008 12:18 PM


Originally Posted by jeff1000man (Post 2428946)
I have one of those blocks. Havn't been able to come up with a good solution to build anything worthwhile out of it.

From what I have read, you can't get a big enough bore to make it worth the effort..

You can stud a 2 bolt block and it will take a 550 HP engine. A 4 bolt would be better, but you gotta use those 2 bolts some times.

They're way thicker that HP blocks. Send it out and have it sonic measured. I've yet to see one that won't take a .100 overbore.

The 2-bolts are fine for mild street motors. Most of those guys spend seconds at max RPM and most don't free rev them and drop the clutch repeatedly.

jeff1000man 02-01-2008 12:23 PM


Originally Posted by Chris Sunkin (Post 2428975)
They're way thicker that HP blocks. Send it out and have it sonic measured. I've yet to see one that won't take a .100 overbore.

The 2-bolts are fine for mild street motors. Most of those guys spend seconds at max RPM and most don't free rev them and drop the clutch repeatedly.

So what would the bore size be. I thought they were 4.25 blocks.

What could you make with it?

Oh, and I thought 550 Horses was mild motor?:D Studded 2 bolt blocks hold up pretty good with the 4" stroke, NA applications. I don't use them for anything longer stroke or with a blower set up.

By the way, thanks for the hook up on the dealer info. :D

jeff1000man 02-01-2008 12:25 PM

THose blocks were built taller so that they could put the taller piston with the extra ring on it to run at high rpms for hundreds of thousands of miles.

proboat-wes 02-01-2008 12:25 PM

who has the pallet loads of heads here at loto?

Chris Sunkin 02-01-2008 12:31 PM


Originally Posted by jeff1000man (Post 2428986)
So what would the bore size be. I thought they were 4.25 blocks.

What could you make with it?

Oh, and I thought 550 Horses was mild motor?:D Studded 2 bolt blocks hold up pretty good with the 4" stroke, NA applications. I don't use them for anything longer stroke or with a blower set up.

By the way, thanks for the hook up on the dealer info. :D

They are. You can go 4.350 and 4.250 stroke with no interference. Gives you a beer-budget 505 and better torque than a 502. Grind a little on the pan rails and the liner bottoms and you'll fit a 4.375 or even a 4.5 crank in there. That gives you 520 or 535. Lov-rev/big torque.

The only advantage you gain with the larger bore on the 502-up is the unshrouding of the intake valve but that's negligible. You trade 10 peak horsepower for 25 ft/lbs torque across the board with the 505.

waterboy222 02-01-2008 12:45 PM

starting to think all this is just way above my head.. I absolutely love my boat so I dont want to sell it and try to find something that will run 90 just to get that speed. Plus I could get about $33k for my boat (if i sat on it for 2 years with a for sale sign cause of this stupid market).By the time i found something that has what I wanted and for that price, itd still be a fixer upper i think..

So there is really NOTHING I can do to these motors to bump the horsepower? Maybe Ill just spend the money on rebuilding the motors and dressing them up a little and be happy with my 70mph and reliability.

Chris Sunkin 02-01-2008 01:28 PM


Originally Posted by waterboy222 (Post 2429035)
starting to think all this is just way above my head.. I absolutely love my boat so I dont want to sell it and try to find something that will run 90 just to get that speed. Plus I could get about $33k for my boat (if i sat on it for 2 years with a for sale sign cause of this stupid market).By the time i found something that has what I wanted and for that price, itd still be a fixer upper i think..

So there is really NOTHING I can do to these motors to bump the horsepower? Maybe Ill just spend the money on rebuilding the motors and dressing them up a little and be happy with my 70mph and reliability.

The reality is you might be able to get 30-40 horsepower with the heads and exhaust you have now. You'd have to replace the cam, manifold & carb. Power comes from increases in displacement, RPM, compression and cam timing- usually at least two or three are required to have some effect. Then you need related componentry on the intake/exhaust
to make it happen.

If you really like the boat, I'd say go for it. You have to stop looking at what it's worth and what you'll be spending. You do need to consider all the expenditures though. There's no sense in getting halfway thru and discovering you can't afford to finish it. At least it runs now.

James 02-01-2008 01:32 PM

Scott is a good guy - the internet and national dragster and PB are great places to advertize and I'm thrilled to hear that Scott has built solid product - but as you guys have expereinced - organization and cleanliness is not his specialty. But Scott alone helps to keep other supplier cheap - for that he is good -


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