i am soooo confused......
just looking for some basic info as i try to spec a new motor..
i am assuming... that most bbc are based on the 454 block as the starting point...but what do i know....
what is the difference between......
1.Gen IV,V,VI ??
2.how do you get to 502, 540, etc.?? by boring and stroking the basic 454???
3. Merlin heads and blocks...
4. oval port vs. rectangular ports....
5. tall block????
anyone have a favorite combo for a 5lb boost, reliable, 650 hp lake motor....and hopefully not he $64k question...what would i expect to pay for this class of motor from one of the popular so cal, arizona engine builders????
thanks in advance..
gary
If you are going to build a 540 BBC you will need a Bowtie, Merlin, or 502 block. THe Bore is 4.5 and the Crank must have a 4.250 stroke.
I am not an engine builder, but I have reaserched this motor combo for my boat.
You may want to call REX Marine they sell a 540 Merlin (Block & Heads) crate motor.
Brent
Gary, here's what I recall;
Gen IV - 2 piece rear main seal,fuel pump boss on block
Gen V & VI - 1 piece rear seal, slightly different head gaskets, no fuel pump boss on block. Mechanical fuel pump is driven off of seawater pump. Timing chain cover on a Gen VI (don't know about V) only has 6 bolts mounting it to the block, composite material. You can't run a true dual roller chain on these motors without an aftermarket timing chain cover.
Max cubic inches you can normally get from a 454 is 496. That's with a 1/4" stroker crank and a 0.060 overbore
502 is a seperate block, 540 is a 502 with a 1/4" stroker crank and (I think) a 0.060 overbore. About as big as you can go with a standard 502 block.
Merlin blocks have revised oiling and block stiffining. A lot more material around the bores. Good piece. As for the heads, I hear yea's and nays. The shop I used isn't that impressed with them. He prefers Dart or Brodix.
Oval ports (intakes)are good for low end torque. For high performance applications most folks always use the square ports. My motor makes 878 horsepower with the GM square ports.
Tall blocks are just blocks that actually have more "block" so to speak in the cylinder bores, In other words picture the piston coming up a standard block, if it was a tall deck it would have more bore to move up in. This is essentially the difference between a 302 Ford and a 351 Ford. The 351 is taller and wider at the intake manifold. This extra stroke on tall deck Chevys are what allows those monster motors of 550+ cubic inches.
Check out Larry Peto at Larry's Speed & Marine in Tucson. He's always got time to explain stuff to customers.
For what you want, 454 with a 250 B&M blower, decent cam, fuel system and ignition. My first motor was this basic set up and dyno'd at 697 hp. E-mail me if you have any questions. mltdwn12@qwest.net
Craig
PAW has a BBC Marine book, the guy that wrote the book also has an ad in ythe back of the new hot boat if you wanrt to order direct. It's really an informative publication on the basic marine chevy and goes into some mild upgrading. A must for any novice bbc guy. (Like myself)
HP books
BBC Marine Performance by Dennis Moore
800-788-6262 ext 1
Great book, has all the info on the different BBC's, heads, etc.
Gary, did you end uyp cutting a deal on the 26 cat?
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