Does anyone know which setup is best for street use?
Been lookin' at Merlins, but I dunno about their oil seal situation.
Any and all opinions welcomed! Thanks!

 

What do you mean by best set up. The block? The Merlin, Darts, and GM Bowties are all very nice blocks. Some nice aluminum ones out therer as well. As far as crate motors a buddy has 5000 miles on a Scott Shaffiroff (sp?) 540 that has run in the mid 10's (71 Chevelle) on pump gas.

 

Either a crate motor or built up- doesn't matter that much.
I'm just wondering about blocks, camshafts, valve trains, heads, etc.
The Merlin 540 crate looks good, but I'm not sold on the MK IV-style oil seals, oil pan, timing cover & lube system; just don't want oil leaks or lifter adjustments, if possible. I also like the ZZ/572, but don't really want the raised deck block.
There's a ZZ/502 in the car now, and it's nice and dry on the outside. Just lookin' for more power, as usual.........
P.S.
Also got a set of GM open chamber, 118 cc rect. port alum heads with 2.25 intake valves; I was sorta lookin' for a short block to put under them.

 

I am not sure that the MK IV seal system is bad with new style gaskets. If you use Fel-Pros one piece oil pan gasket and some of the newer technology seals, I think you would be OK there.

P.S.- So what is the plan for the 502???

 

Thanks for the seal info- I know racers don't really give a crap about minor oil leaks, but it's a PITA for a street vehicle.
I don't know what I'll do with the 502 yet- I was hoping to get some guidance here about other engine choices & setups first- then I'll know better what I'll do with it.
I do like the Gen VI oiling system and one-piece rear main setup- I DON'T like the external balancing, lack of a fuel pump boss, and no forward clutch pivot boss, though.
P.S.
Maybe there are some different forums that might be a better place for help on this one- anyone know of any??

 

There are quite a few 540's around here. Some kind of obscene and some very mild. Just depends on what you want. The shortblocks are all very similar, the differences are in the heads, cam and induction, mainly heads and cam.

The Merlin block is a very nice piece. The out of the box machine work is very good and it's made out of much better iron. They do make the decks relatively tall to my liking, but that way you can machine them to whatever you want. It will take a .020 or so cut to get the pistons "0'decked. Mine are actually .009 OUT of the hole for better quench. I doubt Bill Mitchell messes with it on his crate motors, but it's the little stuff that separates a 600 and a 650-700 hp motor.

The Darts I am sure are just as good. But if you are looking at crate motors, you'll have to dig around to see.

Sounds like you're willing to spend some serious money, but you "could" build your 502 into a 540 pretty easily. Many engine builders crate motors are based on 502 blocks and make great power. You could get a new one piece seal crank, some 6.385 rods and some SRP pistons, have it all balanced internally and be in business other than the clutch boss and fuel pump. In fact, ML67 here on the Forum has a nice set of 4.500 flat top Lunati forged pistons you could get a good deal on. Low miles and you could just bore your block to fit them. This is a nice low $$ way to kick TQ up on your motor.

External balancing is a personal preference, but not a deal breaker on an engine like this. For reference mine is external balanced and does fine (10.0's@139+ on pump gas) even turning some pretty good rpm.

The real difference will be in the heads and cam. Don't be lured into too small of a head. Big motors like big heads! Even Bill Mitchell uses 350 cc or so. You can use relatively smaller port volumes IF you get the CNC versions. Think AFR, Brodix M2 etc. We're going to be getting new Dyno numbers soon from Vettemaniac comparing his 9.5 compression 540 with new CNC 357 cc AFR heads against his previous ported GM/Edelbrock rectangular ports and again to when they were stock. He uses a daily driveable hyd roller cam. It should be interesting to see how they do with large heads.

Don't worry about using a dual plane intake. A single plane will be as streetable as anything with this many cubes.


Keep giving us info and we can help plan one for you.


JIM

 

Jim .You mean 6.385 rods?4.25 crank.

 

OOPS!! Hate it when I do that!

Short little suckers huh?


Yes....6.385 rods!

Thanks,


JIM