afgun

Hi. I need a measurement from the rear (transmission) mounting face on the block to the inside of the clamshell bracket that drops over the mount on the frame.

My (engineless) car has a measurement of 14 inches, but the (pontiac) engine that I'm trying to drop in has a measurement of just shy of 13 inches. Want to know if something in my car is misaligned, or if the SBC and Pontiac distances are different (as I am assuming).


Measurement of Pontiac 301 rear face to motor mount bracket.

Also would like to know your measurement of the pin to pin between the clamshells, if someone has a block with the pan off.

Measurement of Pontiac 301 between clamshells


Thanks!

Vader

No help here. My spare SBC has no mounts on it currently. Someone else will hopefully have one prepped with mounts.

anesthes

iTrader: (12)

Figure it out?

afgun

I ended up buying some aluminum plate and I'm dropping the engine into the car this week to scribe for bolt holes... when in doubt, engineer it out!

anesthes

iTrader: (12)

I think the flat mounting pads on the k-member are going to be very helpful vs a factory k-member for you to make adapters. If you need I can go measure a SBC in the shop later.

The bell housing adapter is going to add some length too, right?

-- Joe

afgun

The factory kmember I believe has the holes for the Pontiac mounts. :-/

If you have access to take a measurement without investing much effort, I'd appreciate it, but not if it will mean much work for you!


Thanks!

OrangeBird

iTrader: (1)

The two different sets of holes correspond to the differences in the V8 VS the V6 engines, and are not "Chevy VS Pontiac" accommodations . GM never put Pontiac engines in these cars

afgun

I had read that the early third gen subframes were drilled for the Pontiac 301. Perhaps not... at around 9:33 in this video you can see the 2 sets of mounting holes fairly close together. I believe that the Pontiac mounts are the slightly lower (an inch or so) and slightly rearward (looks like the front bolt hole is about halfway towards the rear between the original bolt holes) set with the lower hole used in the front of the mount rather than the rear as the third bolt. This image of a third gen subframe

doesn't seem like it has those holes, so I might have needed the plate anyhow.


Comparing the 2, I see what might be the lower and rearmost holes for the Pontiac mount but definitely not the forward hole.

Anyone have an 82 subframe that can check for these holes just to satisfy my curiosity?



Thanks!

OrangeBird

iTrader: (1)

In your video the man is working on a 1978 (second gen) car, those did have the Pontiac engine. Hopefully someone whose done this swap will step in and help you, I just specifically remember reading here that the only two sets of holes were for the V8 and V6 engines.

afgun

Reason I'm asking for this is the car I bought came with an aftermarket Kmember that only has holes for the SBC. I'm going to work around it by making an adapter plate, so my curiosity at this point is largely academic.

NoEmissions84TA

iTrader: (1)

Who is crazy enough to put a Pontiac engine in a Pontiac car?
Just kidding. I hope you can make it work.