Worth getting or NOT, Need Help

[mach123]

Hi Guys/Gals

I am starting to look at things I need to build a 500+ stroker and going to go of a 400 block, I have been reading and researching lots and everyone says spend the money in the heads, so I can get my hands on these heads give me your thoughts good or bad about them, here are the specs.

Indy Alum. Big EZ 325 heads
75cc chamber, 325+ cnc ported
flow over 370
chambers opened up 4.5 from 4.3
metal body viton valve seals
ferrea severe duty 2.25 intake, 1.81 exh valves
Pac 1225 Roller cam springs
titanium valve retainers
10 degree locks and external oil deliv
comes with the offset rockers
So are these worth making a deal with as they are way more at retail or buy something else for same money as I can get these, let me know what I might be getting myself into with these heads for my 512 stroker on a 400 block, any info would help, thanks

 

[451Mopar]

They sound great, but the chamber opened up to 4.5? You would have to check that out, and use the correct diameter head gaskets. The MLS gaskets are great, but expensive.
The PAC springs are good, should have about 250psi seat pressure @ 2.00" install height, and around 700 lbs open @ about 0.700" lift.
I have the same springs on my Victor MW heads, 74cc chambers, on a 499", 4.15" stroke 400 block with flat tip pistons so compression is a bit over 12:1.
With a decent solid roller cam, your looking at a 700+ HP engine. My 400 block is setup with the BCR aluminum main caps and 1/2" thick main girdle.

 

[mach123]

So what is the 4.5 chamber mean good or bad, I also would like to know what the best you can buy for 3000 grand in heads with rockers, just so I can compare with these, thx

 

[Garys1969RR]

I think one thing you have to watch for in a larger chamber head, is that the gasket CANNOT protrude at all into the combustion chamber. As that will cause the gasket to fail. As well as cause a hot spot that can lead to detonation.

 

[mach123]

Thx for the info, I will research it more.

 

[Propwash]

That a good point on the gaskets Gary made. You can buy head gaskets for bored engines to match. Those are some pretty serious heads for a street car. What is your end goal? Those will work awesome if you're looking to get into the 650 and beyond Horsepower range with your 512. For $3,000 bucks I guess they better..lol Honestly if you're not running a big cam to really open up those valves and keep'em open you're probably spending more than you need to. Large intake runners aren't going to do you any good if there isn't big air and fuel coming into them. I wouldn't waste your money and go overkill if you're just looking for a decent street motor. That can be done with decently ported cast iron heads or mildly ported/cleaned up aluminum heads (like the Eddy RPM or 440 source heads).

 

[mach123]

Ok Thx yes that is what I thought about these heads, I don't want over kill, even if they are worth 6 grand new, I will look at other choices and find the heads I need and then go from there on the rest, thx again guys.

 

[Propwash]

Here's a a good little article from over at Hughes that gives a comparison on a few different head CFM's that you might enjoy.

http://www.hughesengines.com/TechArticles/1headflowchartscomparisons.php

 

[383man]

I use the standard Indy EZ heads on my 493. I bought them from Dwayne Porter and he did some minor porting on them as they flowed 329 @ .600. Those are bigger runners and flow more then mine. I really like them over the Stealth and RPM heads because if I want to step it up more down the road these heads seem to have more potential then the Stealth and RPM heads. You have to decide if your build will be nasty enough to use them. One thing I like is my EZ heads still use stock exh port location and use internal oiling to the standard demention rocker arms and shafts. Here they are on my 493 and they painted up just fine. These heads are strong enough to push my 3700 lb 63 to 10.70's so far on 92 pump thru the pipes and driven the 90 mile round trip to the track. Ron

 

[mach123]

Thx 383man, great info I am starting to strip car down, while I think about what route I will take. THX