452 Head & Valve Question

[Killer_Mopar]

Does anyone know the stock size valves for 452 heads? I always thought they were 1.74 exhaust and 2.08 intake. However, I was searching around on ebay and two people said that there heads had 1.73 exhaust and 2.14 intake valves. Which is the correct size? Also, will the 452 heads accept 1.81 exhaust and 2.14 intake valves?? Lastly, about how much cfm will a template ported 452 with 2.14/1.81 valves flow? Thanks.

[rumblefish360]

Click here and scrool down for links. http://www.moparchat.com/forums/showthread.php?t=87053

[DartGT66]

They have 2.08/1.74 valves stock just like all other '68 & up mopar BB factory heads. You can install 2.14/1.81 valves in tehm, but you'll loose the surface hardening in the exhaust seats, so you should have hardened seat rings installed for longevity if using unleaded. This all often ends up costing so much, that new Edelbrocks become an attaractive alternative. Check out ,opar muscle magazines tech archivers about BB heads and their porting, it will answer most of your questions.

http://moparmusclemagazine.com/techarticles/5115/
http://moparmusclemagazine.com/techarticles/5118/
http://moparmusclemagazine.com/techarticles/5120/

[dkn1997]

Ported 452's / Stock

Lift Intake Exh / Intake Exh
100 60.7 54.6 / 58 49

200 132.5 107.1 / 118.4 103.5

300 195.5 148.1 / 162.0 132.2

400 233.0 170.0 / 186.1 142.7

500 246.0 178.0 / 195.7 146.2

600 252.0 181.5 / 207.1 148.5


The ported 452 numbers are for a set I had with stock 1.74/2.08 valves. These were fully ported heads w/3 angle valve job. the stock numbers I got off a website somewhere, they may be for 906's, but all the open chambered big block heads stock flow similar. These particular heads had no work done to the bowls or the short turns. That is where you can pick up a lot.

basically, you could come close to the eddys with porting, big valves and a good valve job, but unless you do the work yourself, the eddy's make more sense....

[23T]

I'll tell you my experience 456 heads full port & polish ( got a cut rate for trading labor), 60 milled off heads, 74 milled off intake, new hard seats in exhaust, new 2.14/1,81 SS valves, new springs retainers & locks = $1210.15 and I had the heads, wish the eddies were out before I spent these $$ still myself

[DartGT66]

It's true that the open chamber stock flows are very close, but the flow numbers from different flow benches and users might not.

[TL]

Is it safe to say you add 50 cfm to the intake and 20 to the exhaust if you do a good job?

[DartGT66]

Check the articles above adn check the numbers, there you can see how much work is neede from a "semi pro" to achieve that kind of results.