PM-7 question??
 

Hey guys, I bought this pm-7 this afternoon. Got it home and started looking it over a little closer and noticed this on the bottom, has anyone out there ever seen a pm7 with this weird glob on it??

At first I though maybe it had been cracked and this was a repair job but upon closer inspection it really looks like part of the casting?

Also if I polish the runners will this flow better? I’ve heard they’re terrible intakes performance wise but I just love the way they look :)

Thanks!!!

Re: PM-7 question??
 

Not sure there is any reason to worry about a casting flaw in that area.

Re: PM-7 question??
 

There were 2 different casting runs of the PM-7's as far as I am aware. if i remember correctly the one with the "glob" is the earlier of the 2, thought I'm not 100% sure yours is the same as the normal "glob". I'll have to look at mine to compare. I'd imagine yours has a number stamped on the bad behind the generator mount? If so, what is that number?

Re: PM-7 question??
 

I I didn’t see any number stamped in it?

Re: PM-7 question??
 

Mine has the same plug. I thought it my be to remove the sand from the inside that area.
First that I have heard they were poor performance intakes.

Re: PM-7 question??
 

In my experience the PM7 works better than any Eddie Meyer but not as well as an Edelbrock slingshot.

Re: PM-7 question??
 

I think the poor performer tag came about when Hot Rod magazine did a manifold shoot out a few years back. In their testing, it performed poorly. That said, thousands of folks have run them and had good running motors.

If you like it and have it, run it. I have one as well. I checked and mine does not have that plug. It does look like a by-product of the casting process.

They look great in a '32 engine bay for they fill up the space nicely.

Re: PM-7 question??
 

A friend of mine ran one on a 276 .L-_100 engine. semed to run pretty good. A street intake is measured by it's throttle response. I don't think it was made for Bville.

Re: PM-7 question??
 

Here's the Hot Rod article if anyone is interested: https://www.hotrod.com/articles/hrdp...old-smackdown/

The link may have a problem!

Re: PM-7 question??
 

Could it be that's nothing more than just the spot where a sprue or riser was cut off and then machined smooth when the intake was being machined?

Re: PM-7 question??
 

Looks like the remnant of a sprue or riser to me, too.

Re: PM-7 question??
 

Thats a common site under original Thickston intakes. You ask about polishing the runners your going to get a lot of answers some for and some against. My thoughts are it couldn't hurt just go easy try not to open up the runners as you go along if you decide to do it. I have seen a few intakes ruined by getting to carried away on the runners and then trying to match the intake ports to oversize runners causing a big headache trying to save the block just be careful. ;)
Ronnieroadster

Re: PM-7 question??
 

I always thought leaving runners in side the intake rough allowed the gas to vaporize better. Am I wrong?

Re: PM-7 question??
 

Fuel tends to drizzle if it's too slick inside there. The port area would be the best place to smooth since it is a convergent duct of sorts but It will only do so much for breathing on a flathead. I'd leave it rough myself.

Tommy Thickstun had a design that was competitive but he was kind of hard headed as an engineer. He poo pooed Vic's design but Vic's design was good. I don't know if that was professional jealousy or what but the two didn't get along well after that. Vic Edlebrock Sr was a displaced Kansas farm boy with a lot of common sense. Sometimes is doesn't take an engineering degree to get good ideas. Both of them died too young though.