452 head transplant help

[Phoenix440]

 

[Geoff 2]

I measured the depth of the 'open chamber' section on 452 & 346 heads & they were 0.100-0.120" un cut. This may give you a clue as to whether theheads have been milled.

I would also:
- machine the guides for 0.530" seals
- Comp #26918 beehive springs
Beehives require less spring pressure, easier on the valve train.

I would also change cams. If the cam has ~460 valve lift & doesn't get underway until 3000 rpm, then it is poor cam. I would use the Isky 270 Mega cam. A good all round performer with reasonable idle with off idle grunt.

 

[493 Mike]

Only the plug size. I've seen a few on here that someone used the non taypered plugs. It's the reason for the bump so you don't use the wrong style plug. Nothing else different that I know about. Many are using them.

Another tid bit about 452 heads. They have a ridge above the exhaust ports that could interfere with some headers. I had to grind a bevel on the flange for it to fit flat.
View attachment 1909518

View attachment 1909519

When I put Hookers on my new 75 3/4 ton 4wldr, I used two sets of gaskets to get the clearance.
Mike

 

[PRHeads]

From your earlier thread……..
I don’t know if this is an optical illusion or what, but it looks like there are “humps” on the tops of the intake runners on whichever head that is.
I don’t recall ever seeing that before.
What’s the casting number on that head?

View attachment 1909484

New day ………fresh look at it………it’s an optical illusion(to me).
I was seeing the roof tapering down towards the spring as being a raised area.

That’s what you get when you’re analyzing pics on your phone……… carry on.

For a more useful tidbit……
The PAC-1900 springs are the equivalent to the Crane 99839.

 

[PRHeads]

This is how I deal with the guide/seal situation: