mcb55-210

I purchased a Mac's Pivot Plate last year when I pulled the engine out of my '62 for detailing. The plate mounts on the intake, using the carb mounting locations. Obviously, I used it again to reinstall the engine. After blowing up the engine in June, I used it again. Greatest way to pull/set an engine.

My father-in-law is working on one of his buddies '55 Bel Air, and needed to pull the engine. He did not want to use the pivot plate, for he didn't think the four 5/16" bolts in an aluminum manifold would support the weight of a small block Chevy with a transmission mounted to it.

Frankly, I have no concerns setting my almost-finished small block in the next couple weeks, and will do it with the 4 speed attached (although I have a cast intake).

Any comments?

Mike

JohnZ

The cross-sectional modulus of those four 5/16" carb studs is more than adequate to support a complete engine and transmission. I don't know what a "Mac's pivot plate" looks like, but I'd be more concerned about the design of the pivot than the carb studs.

Dr L-88

I used one (not that particular brand) to remove my 327 and Muncie 4 speed and then install an aluminum 427 with Richmond 5 speed attached. No problems for me. Just be careful.

https://www.corvetteforum.com/forums...minum-rat.html

SupremeDeluxe

Tensile strength of a grade 2 5/16" bolt is greater than 3,000 lbs.

claysmoker

The MACS plate is more than up to the task. It's far stronger than the 5/16 bolts that hold it in place.

buns

Your father in law is a wise man. It's not the strength of the bolt that is the issue. It's the strength of the threads in the cast aluminum.

mcb55-210

So if the threads of the aluminum intake are the weakest point, how would you determine the maximum weight that could safely be supported?

Mike

JohnZ

Dunno offhand, but NASCAR teams have been yanking complete engine/transmission combinations using a carb plate on an aluminum manifold for over 50 years, and I've never seen them drop one.

MikeM

In my opinion..........................

The easiest way to deck an engine is to do a two point hookup on the heads at the center exhaust port on each side. the engine is balanced fore/aft and the center of gravity at that point is almost neutral.

When you hang it from the top of the intake, the balance is all wrong unless you get the balance exactly right for each custom installation.

Personally, I would never hang and engine from four studs screwed into unknown threads in an aluminum intake.

Just my opinion.

mashinter

The torque spec on the carb nuts is a measure of the total joint strength, including the aluminum manifold; doesn't look like the aluminum is an issue for a manifold in like-new condition.

But I have had to use an insert in an aluminum manifold to repair damaged threads if bolts were used and over-torqued or if the bolts were too short for full thread engagement.

MikeM

Exactly. Unless you know the condition of those threads, you are taking a big chance. A chance that can result in a lot of property damage and personal injury.

No, the sky isn't falling, just my opinion again.

I've seen a fair number of intakes with the carb threads screwed up and damaged.

Kerrmudgeon

I personally used bolts into the heads as well, BUT my engine builder buddy uses those plates all the time around his shop and has never had a problem. I just sleep better at night knowing the steel bolts are there.

I do love that plate pivot thing though......it keeps the crane end very close to the motor for any clearance issues with the range of the jack. Nothing worse than running out of height when trying to get over a fender.