270 GMC altered motor build part 1

Cool motors alright.
I have one in my workshop.
It's an old racing motor with a "3/4 race" cam etc ..

...

 

That would make sense, since it is a six cylinder, not an 8.

Six/eight = 3/4.

 

If you have trouble pushing out the head gasket even with the oring, you can put a receiver groove in the head. That is a tried and true deal with copper gaskets and high boost.

But I prefer the oring to be in the head and the receiver groove in the block because if it does blow the gasket it is more apt to blow it in the groove rather than around the stainless steel oring. The flame can be kind of ruff on the aluminum head. JC

 

We have roller lifters and rockers , I have no clue who made them ,they were a swapmeet find . I'll post some pics later
Marshall

 

???

 

HAHA! It's a joke dude!

A 6cyl has 3/4 the cylinders of a v8. Therefore, instead of a full race cam,it would only have a 3/4 race cam.

Get it?

 

Geeze I'm slow ... lol

 

more pics!!!!!!!

 

What is max bore on a 270 block?????? I'm doing one as a street motor for a friend, I was told .125 was the max for the 270.....thanks

 

Most guys bored them to 3 15/16. Which is .156 over. That's a lot. But I did it and the thing lasted forever. If yours falls through I never told you it wouldn't.

 

Some more pics.
We got the short block done last night .
Mike got the pump drive made for the timming cover.
The head is almost done
Its getting there
Marshall

 

Heres some more .

 

Looking good, Marshall!

I love that Wayne Horning timing cover!

 

Rare piece. I had one of those covers on my Howard Head 302. Got the mag out of the exhaust stacks. Didn't need the oil or water pumps. Sold that engine to the Salt Circus guys.

 

Heres a couple more timming covers we have here

 

Marshall, I can see that I need to be best friends with you! Lol!

 

Great build, I'm digging the updates Marshall and can't wait to see it finished!

 

What kind of rear main seal?????? and thanks again....

 

Rope seal with graphite in it ,some new stuff I've never used one ,hope it works

 

As I remember I used a '49 Ford distributer drive gear set on my GMC with the Horning cover. Is that still what's happening? Seems like they wouldn't be a common these days.

 

What did you use for a mag? I have two one that just goes in the block and one that has to have the tac drive adapter,and that are both to short for the Horning cover.
The GMC gear works.


Salt Circus , George Campbell cool car, I bought a 32 ford PU from George.

 

I had a Vertex. It was still on the motor when I sold it to George. The gear on a '49-53 Ford/Merc slides on the front of the cam and is replaceable. The GMC gear is machined into the center of he cam. I got my cover like yours without a shaft for the extra Cam drive gear that turned the Mag, Oil pump and water pump. Had to make one. No biggie. But I used Ford distributer drive gears to drive the mag.

 

Marshall, I have a rebuilt Ronco, earth magnets and mechanical tach drive, that you could borrow if it would work for you.

 

Heres the head and rockers all done.
Now all we need to do is clay the valves and make sure its going to work.

 

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Wow! What size valves are those?

 

Straight In & Straight Out....that will work....

 

1.82 intake
1.70 exhaust

 

Monsters!

Are those the Skinner rockers, or different ones?

 

I think the rockers are the ones Nick (whats his name) use to sell.
The valves started as Mopar B1 race valves and they were 2.25.