valve size

[cwhubb]

will 2.14 intake and 1.81 exhaust valves fit stock 440 heads? 906,452's
Thank you

 

[RustyRatRod]

Yup but the heads have to be machined for them. You need to be careful though. 2.14 and 1.81 valves are overkill for all but the absolutely most extreme builds. They just aren't necessary and can actually hurt performance in some cases.

 

[cwhubb]

Thanks Rusty, I didnt know about the performance dynamic, is it because of the loss of velocity with the big ones?

 

[IQ52]

Yup but the heads have to be machined for them. You need to be careful though. 2.14 and 1.81 valves are overkill for all but the absolutely most extreme builds. They just aren't necessary and can actually hurt performance in some cases.

That so?

 

[cwhubb]

alot of the performance / and modified iron heads advertised have 2.14 /1.81 as upgrades and there listed as street/strip applications. all the options gets you to second guess, confuses things.
what I'm looking for is my engine combo to be a very mean street car
my combo:
4000lbs car including driver
440 bored .30 over
10:5:1 kb pistons
290 crane fireball 234/[email protected] 494 lift with 1:5:1 stock rockers.(I have a 242/246 lift @.50 555 intake lift, sitting on the shelf)
4:10 dana 60
m1 single plane
750 holley
stock 906 heads
b&m reverse pattern manual shift 727
3500 b&m hole shot converter

 

[67 coronet]

alot of the performance / and modified iron heads advertised have 2.14 /1.81 as upgrades and there listed as street/strip applications. all the options gets you to second guess, confuses things.
what I'm looking for is my engine combo to be a very mean street car
my combo:
4000lbs car including driver
440 bored .30 over
10:5:1 kb pistons
290 crane fireball 234/[email protected] 494 lift with 1:5:1 stock rockers.(I have a 242/246 lift @.50 555 intake lift, sitting on the shelf)
4:10 dana 60
m1 single plane
750 holley
stock 906 heads
b&m reverse pattern manual shift 727
3500 b&m hole shot converter

not gonna get much improvment putting those valves into stock heads.i have several sets that run great on the street,but they are all ported and polished.no need to put a man hole cover on a kitchen sink,if you get the flow reference.

 

[Cranky]

Intake valve diameter, intake valve duration and intake valve lift factor in together to determine air velocity in the intake system. Large valve diameter, long duration and high lift all allow the engine to breath better at high RPM, but also cause the air to move slower at lower RPM, which reduces power/torque in the lower range. Small valve diameter, short duration and low lift all cause the air in the intake system to go faster, which increases power at lower RPM, but chokes air flow when the air velocity reaches the speed of sound. So you need to think about where your engine will be most of the time and what you want from it. Larger valves will require head work (ports) in order to maximize the valve size. Btw, just doing bowl work will improve the flow of stock heads a noticeable amount even with stock valves. Pull a valve out of a stock head and you will see a performance nightmare in the bowl or pocket area. The under cut sucks and the protrusion of the guide is just as bad.

 

[RustyRatRod]

That so?

Probably not where you're concerned cause you hog the heck outta your heads so they could probably flow a 3" valve. lol

 

[rev.ronnie]

If you don't open up the cross sectional area in the runner and the aperture under the valve to match the valve diameter, you won't see any gains...like RRR said, it will probably hurt.

The velocity at the seat will decrease and hurt atomization. Porting a stock head that much may result in hitting water on the short turn. I've seen it too many times.

 

[RustyRatRod]

That so?

Feel free to go farther than two words. If I'm wrong, I wanna learn sumffin.

 

[Meep-Meep]

Yes, they will fit with machining but as mentioned you will need to open up the cross sectional area of the port to get any real benefit. I have them in my 440 and I don't think I killed the heads by putting them in, but could have probably saved the money and kept the stock valves and NOT hurt my performance. The actual head diameter is only .070" larger on the diameter over the stock exhaust valve and the intake is .060" larger, or about .190" difference in circumference. It can also be said that installing a larger valve is like adding some cam duration.

 

[IQ52]

Lift..............452 head Stock............install 2.14/1.81.............blend throat into bowl

.100.................61/55............................64/56...........................67/60
.200...............130/108.........................133/114.......................137/130
.300...............188/152.........................187/149.......................199/187
.400...............213/172.........................211/166.......................239/218
.500...............227/178.........................224/170.......................256/234
.600...............230/181.........................229/171.......................262/245
.700.......................................................................................265/253

Exhaust was run with a 2" pipe.

 

[RustyRatRod]

Blending the throat really makes an impressive difference.

 

[Cranky]

Had a set of max ported (professionally done before I knew much about it) that flowed just as well as a set of out of the box Eddy RPM's. What ones do you think would run better in the real world? When you look at the design of the 'better' Eddy heads, you would think that they would perform better than a same flowing max ported stocker that flowed the same numbers....and you would be right. Flow numbers are only a tool but real world testing will tell you the truth.

 

[IQ52]

If those "max ported" iron heads didn't outflow the OOTB Edelbrock RPM heads, then they were not max ported.

I haven't personally tried a heads up comparison with a factory iron head that flowed the same as an Edelbrock RPM head so about that I won't say.

 

[383man]

These are a set of 906's I ported and installed the 2.14 and 1.81 valves in myself. The car ran good but I never put them on a flow bench. Ron

 

[Budnicks]

Hey Jim/IQ52 I have a different question... what's better ??, to blend the port throat entry to the bowls ??, or the short side radius under the valves ??, especially when you add larger valves... I know "both" should be done, but witch makes more differences in flow ??, also should either of them them, be baby smooth ??, or a slight texture left in them ??, I'm just curious, that is if you've tried flows with just these portions of either done 1st... Thanks in advance, from your friendly cylinder head question pest...LOL... A very smart man, well versed in performance &/ or race engine builds, once told me that, "the 3 most important things on a performance &/or race engine build are, 1st CLYINDER HEADS, 2nd Cylinder Heads, last but not the least 3rd cylinder heads

 

[cwhubb]

You're right Cranky, I've been seduced by performance parts that didnt make a bit of difference, looks great on paper but real world results were under whelming. Through luck and perhaps Devine intervention I met Roger Harlow, back in the day when Ma Mopar commited to the muscle car line he was an engineer from the R&D department for head design. He did heads for Landy and Barton back in the day, in fact the first ever set of zoomies were bolted to his heads.
Ok enough name dropping, He says the same thing, quote "******* numbers don't mean **** it's the real world results that count"

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the valve may only be .070, and I agree one on one it's not much of a difference but multiply that by 8 and it's a significant amount over stock size. one .30 over cylinder isnt much but put all 8 together and you have something