70 390 intake info.(Machine vs non-Machine) types

Updated with reinserted pictures 12-16-17

 

This post is kind of an addendum,to another post dealing with the differences between the 1966 -69   290/343 4bbl intake ,and the 390 4bbl intake.

 

While doing some comparing a few months back,I took these pictures of a stock intakes used on the 390's in 1970.

 

AMC basically used one 390 intake for all 1970 390 application except for the Rebel Machine.

 

The garden variety  1970 390 intake was ,casting number 3199532C or 532C(which was also used on the 360 4bbl)  (390 Ambos AMX's Javelins etc.)

 

The  intake used on the Rebel Machine or (Machine ) was casting number 3199762C or 762C (Rebel Machine only)

 

The first group of pictures are if the 532C intake( 4 pictures)

 

The next group of pictures are of the 762C intake (4 pictures)

 

The last is of the intakes side by side.

 

My observations are that the real differences between the two intakes is the obvious 532C four hole vs the 762C's two large oblong holes (left and right side) configurations, but more importantly is the way the two are cast.

 

The 532C four holes are machined into the casting,and leave a sharp lip for the intakes charge to navigate around right after clearing the carbs base plate and entering the intake runners.

 

The 762C's intake while some of it is machined,it is evident that that same area off of the carbs baseplate that enters the intake runner is "CAST" as a radius ,to aid in the transsition for the intake charge entering the runners.

 

The measurements show that the intakes have the same distance from the respective intake floor (left and right side) from the carbs base surface.

 

I dont think that anything is different inside the intakes,as a matter of fact,they probably took one of the molds for the 532C casting and modified the top portion only to make the 762C intake?

 

I'm pretty sure that the pictures do at least a decent job of showing the radiused edge difference ,between the two intakes?

 

Here's the pictures ,and I hope that this helps!

 

Rich Corsello

 

 

Stock 1970 360 & 390 intake casting number 3199532C

 

 

 

 

1970 "Machine intake"(Rebel Machine only) casting number 3199762C

 

 

Side by side comparison

 

 

 

 

 

 

 

 

 

 

Peter,as far as I can tell,if you were to take the stock 70 intake (532C casting ) and cut the center stock out seperating the primary and secondary bores ,on the right and left side respectively,then go and radius the corners at the front of the primary bore and the rear of the secondary bore on the left and right side ,you've got an intake manifold that will perform like a Machine intake would.

 

Now , I should have measured also from side to side ,or made a template too ,then compared.But that's going to have to wait till I get my Machine intake ,un -hijacked from my friends house.

 

Rich C.