Thread: 468 Bbc

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Hey guys I have a 468 BBC in my airboat and was wanting to see if yall could help me out with a horsepower/torque estimate. I don't know all the specs but what I do know is that it is pretty much stock except for a mild cam and RPM performer intake to go along with 830 Holley carb. Thanks.

i did a air boat l think it was 15feet long with a 526 big block chevy you need to give me more on the 468 build to nail down hp and qt if that all you have 400hp??more less hard to say

Originally Posted by pat mccarthy

i did a air boat l think it was 15feet long with a 526 big block chevy you need to give me more on the 468 build to nail down hp and qt if that all you have 400hp??more less hard to say

What do you need to know about it exactly?

Originally Posted by justinduke

What do you need to know about it exactly?

well the more the better what heads you have or casting numbers any work done to them big valves bowl work .how much CR you have cam numbers

Here is what my brother sent me about it:

Camshaft pn erson cam e120201 grind no rv15h
Duration as advertised 288 at in and exhaust
Duration at .050 214 at in and exhaust
Gross Lift .492 at in and exhaust
Lobe Center 112
1250-4250 Rpm Range

60 over TRW Flat Top Forged Pistons
96cc chamber heads off of 427 67-69 model camero, chevelle and corvette.

Should be about 9.5:1 cr

Edelbrock performer intake

Holley 830 cfm marine carb

This is about all I know about it. The casting numbers for the heads are 3931063.

I'd say pretty close to 400HP, maybe a little less. But you could definately use a little bigger cam and benefit from it. The flow of the heads, if they are stock... will support around 5000 rpms on a 468, so when looking for a new cam look for something in that range.

in a air boat you do not want a big cam you can not go much past 4500 rpm ..this would have to do with what gear box you are running if you over run the prop bad things will happen ...hi 300 hp

Thanks for the help guys. I don't have to worry about over spinning the prop because it has a 2.68:1 gear reduction. What would you guys suggest to get this motor up closer to 550-600hp?

Do you really need more? What are the power/speed requirements of the prop?

Kitz

Originally Posted by justinduke

Thanks for the help guys. I don't have to worry about over spinning the prop because it has a 2.68:1 gear reduction. What would you guys suggest to get this motor up closer to 550-600hp?

If what you have is stock, a whole lot more. Im usre Pat and Erik will give lots of suggestions.

Well I would at a minimum like to have 500hp at least. Pitched almost like I want it the motor is only turning 4k and I would like to be at 5k with the same pitch or maybe some more pitch. It's pushing a 18x8 airboat so it's a lot of weight.

the one i did is about 480hp but i think what you want is QT more then any thing so the bigger the better on cid i would do a 496 or 511 one would used a 4 1/4 crank that would be a 496 and the other is a 4 3/8 crank i have done both the 496 is easier to find a shelf piston for it.

We just rebuilt this motor so it's gonna stay a 468 for awhile at least.

same prop as the one i did is has on it??

a new cam some thing with a lsa of 108 or less and carb i think is to big