452 heads

[Tang1964]

Does any one have any experience in shaving a set of 452 heads ? How much would I have to shave them to gain a point of compression ? 50k ?
I’ve read they’re a decent head. I was just thinking I could pull the heads off have them shaved run some mls head gaskets. Maybe slide in a cheap cam. Just to wake up my motor home 440 on the cheap.

 

[BeepBeepRR]

You could go with a thinner head gasket to gain a little. Problem with motorhome engines is that the piston is down in the hole. Others have more know how than I maybe they will chime in.

 

[moes]

https://www.forbbodiesonly.com/moparforum/threads/milling-452-heads.68243/

 

[Tang1964]

I’ve read that 45k only raised compression a half a point ish. So I figured with 50k and a thinner gasket (mls). Would probably only net me 3/4 of a point. But that in itself should be an easy 50ish go. Idk really know all the numbers and stuff. Just rounding everything off that I’ve read.

 

[66Satellite47]

You need to measure the chamber volume first and the deck height before doing any milling on the heads or the block. I'm pretty sure .030 on the head is real safe, and include milling the intake face accordingly. Then pick a head gasket thickness to get where you want.

 

[jeepthrills01]

.075-.090...but then they usually crack. If they are still 90cc...Id go .080 and .1 on the intake...use a steel shim if you have em.

 

[PRHeads]

If the motor is still as from the factory, doesn’t it have thin head gaskets on it already?

The lower the compression ratio, the less change you’ll get from each cc of unswept volume(area above the piston at tdc) reduction.

Milling the heads .050” will take out about 10cc’s.

A totally stock 452 headed MH 440 could easily be under 8:1 from the factory........ in fact it’s likely.

With the CR that low, 10cc’s less volume will get you about 1/2 a point of compression.

 

[Master Gunner]

As mentioned before, make sure you remove material from the intake side so your intake will seal. The rule of thumb on this is for every .010 taken off, .012 is taken off the intake side.

Mark

 

[Tang1964]

10cc seems like a significant amount.

What I am wondering here is. Can I just shave the heads on my mh 440 to make a nominal gain ?
I already have some headmens going on it and an edlbrock sp22p440 (whatever). I’m sure the factory cam is ****.
But what’s going to bring the numbers up better. Some more compression ($300) ? Or some more Cam ($300)?

 

[jeepthrills01]

The SP2P will severely choke that motor. Itll make good torque untill about 3500...then fall on its face.

 

[Tang1964]

I had heard that about that manifold. But 95% of what that guy says is bull ship….. So to get the best out of that 440 I’ll need a different intake

 

[66Satellite47]

The SP2P is junk. It didn't last long at all on the market. The ports were WAY too small.
IMHO a 6-8 CC gain is worth it on a 452. They probably started in the 88-90 ish range. A deep cut valve job to remove the ridge under the seat does wonders.
The correct cam for your combination can make a huge difference. A motorhome cam is not designed for any performance.

 

[PRHeads]

The Sp2p is a noticeable step down in power from the stock manifold.

One thing that generally needs to be addressed on 452 heads if you’re planing on using a cam with near .500 lift is shortening the guide bosses.
Also, if the heads are set up with exhaust rotators(which many MH 440’s are), then those need to go, along with the 2 groove exhaust valves........ to facilitate the use of springs suitable to accommodate the new cam.

This is how I handle the guide boss situation......

 

[IQ52]

Does any one have any experience in shaving a set of 452 heads ? How much would I have to shave them to gain a point of compression ? 50k ?
I’ve read they’re a decent head. I was just thinking I could pull the heads off have them shaved run some mls head gaskets. Maybe slide in a cheap cam. Just to wake up my motor home 440 on the cheap.

Raise the compression? If you want to, okay.

But you can wake up a motor home engine and never touch the short block just by returning to the glory days of 2013.

Cam and cylinder heads could help. I don't recommend the cam that I used. I just used it because it was already paid for and laying around on the shelf. And I believe that better cylinder head airflow was more improvement than a little compression.

Just something to think about.

https://www.forabodiesonly.com/mopar/threads/dyno-testing-a-stock-1972-440.249866/

 

[PRHeads]

A deep cut valve job to remove the ridge under the seat does wonders.

Recondition the seats and a quick bowl blend can pick up 20+cfm of flow.

 

[Runcharger]

Honestly I don't think you'll gain much efficiency for all the work of milling the heads, milling the intake surface etc. To do it right you'd have to change heads to 516, add hardened seats, mild porting, change intake manifold and it goes on and on.
The fastest way to get where you're going is a turbo and leave the engine buttoned up.

 

[PRHeads]

Years ago I re-ringed a few high mileage 400’s, which are all low CR from the factory.
I also added the usual hot rod parts........ intake, carb, headers, cam.
They all ran surprisingly well......despite the rather low cranking compression numbers.

Here’s an example of someone messing with a MH 440:


And more reading:
https://www.forabodiesonly.com/mopar/threads/another-very-mild-440-build.482202/