Cleveland heads

[cgarb]

I have a set of 4bbl Cleveland heads to freshen up/improve this year for a friend of mines son. Fox body mustang, flat top .040 over cleveland with a .585 lift not sure of exact specs solid lifters cam. Car run pretty decent as is, it's a low budget 1st race car for a 17 year old. The end of the year they added the intake and exhaust port plates and the car picked up and ran a 6.99 in the 1/8th. I know I don't want to go in there and hog them out, I'm looking for what the best bang for the buck improvement will be for these. I was going to contour the guide boss and work on the short turn some and try to blend in the chamber some. Do the cleveland heads respond to steep seats like 50 or 52 or is that a waste of grinding stone? Any advice on these would be appreciated.

[fordified]

Closed or open chamber? Closed chamber heads are much better. Better chamber and more compression. Hopefully that’s what he’s got.

Short side and bowl work on the intake side but be careful on the short side. They can be real thin.

If they’re closed chamber heads you can unshroud around the back corner and side of the intake valve but don’t go wild.

Fill the intake runner floors with epoxy and blend into the short side angling the floor slightly higher toward the right where it meets the short turn. Try to make the ports a lot smaller by filling up that floor.

Don’t bother with the pinch area.

Use the exhaust plates and work the short side a little but be careful. It’s thin there too. Keep the bowl as small as possible on the exhaust. Do a little blending that’s all.

Stay away from steep angles.

[Steve.k]

Clevelands dont need much. We cut ours at 45 till we get bigger on cam. The current engine runs .657 flat tappet. The biggest gain in porting we find is just below valve. Short turn has gains but can go sideways quick. But most heads are like that. If your limited to cam size you can see gains from porting. Fwiw Brent Lykins made 620hp on completely stock heads no porting. Im not sure what he used for valve angle.

[cgarb]

Yes, these are closed chamber 4bbl heads. How small can the chambers be made with a flat mill before they get too thin? The block needs a line hone, so while it's apart they are going to have the motor decked. The piston is below deck .025", I know cleveland's can be quirky so that's why I am asking. I don't want to go hog wild and cost me a bunch of labor and make them worse. Just looking at them not having them on a bench my first thought was unshroud the valves, contour the guide bosses and blend the bowl and shot turn. I was not going to touch the rest of the ports. They have the port plates so would filling the intake ports be necessary if they run the plates?

[Steve.k]

Are you talking the exh plates ? Or the mpg intake plates?We dont run anything on intakes. Even Dynoed them never seen gains.I try to get everything zero deck and i have a set of boss 302 heads here at 49cc.

[fordified]

The short turns can be thin especially on the intakes. Blend them back just a bit. I would absolutely fill the port floors with slash zone epoxy and blend it in to the short turn. The ports are too big. You can make them pretty small so long as the short turn is shaped to slow the air down to make the turn. Raise the floors to the height of the short turn all back to the way to the port entry.

If you have a bench great. If you don’t either make one or get access to one. Pay attention to air speed at the short turn. Work the short turn top and bottom if the airspeed is too high.

Work the bowls to make them oval not round. You should put epoxy around the stem boss and blend into the bowl in a teardrop shape.

Go slow and make small changes and retest on the bench.

Don’t spend a lot of time on the chambers. Unshroud the corner and a little on the side away from the corner until the point where the valve has room as cast.

[Steve.k]

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This is a set we did for mud truck. No fillings or plates.

[Steve.k]

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These are filled expoxied etc. Ex prostock head from a guy in Florida. Heavily modified. Heres pics.

[Kenny M]

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Like Steve K said.. They really don't need much. I just built a 383 with very mild head clean up work and with 12to1 and a cam that is 260 at .050 it make 625HP. 585 with the stock intake manifold. These heads flowed 325 non touched port with bowl clean up.

I did test a set of the MPG brass EX. tong's a while back and saw nothing , on a 525HP 347.

I will be on the Dyno on the 10th of this month with a 347 Boss 302 . these heads flowed amazing they must of started as a very good core with just a bowl clean up and a good valve job nice .080 wide bottom cut they flowed 337 airspeed was 260. being it is a smaller engine, i installed the aluminum Parker port stuffers, i feel that these are the best.. It did loose some air flow at .500 it went from 300 to 290 and at .650 from 337 to 320 but air speed picked up to 300 ft/sec.. With some PR pinch work and cutting down the port plate on the PR side floor, i did get the flow back and kept the air speed at 300. My port stuffer ended up looking alot like Steves picture of the epoxyed port.

[fordified]

What’s the airspeed and cubic inches?

For drag racing in a 358-363 the ports have to be filled to be a player. The dyno and track are proof.

I know that to be a fact.

[Steve.k]

What’s the airspeed and cubic inches?

For drag racing in a 358-363 the ports have to be filled to be a player. The dyno and track are proof.

I know that to be a fact.

On my top chart you will see velocity is 296. We always shoot for 300 ish without getting into filling. We ran those heads on 408. I have another running 357 cubes. Im undercammmed on 357 and I know it but our bottom end is to light in strength so we haven’t pushed it further.

[fordified]

Those filled heads look like the old school roush heads. I never understood the port wing idea.

[cgarb]

With those stuffers or plates in the intake what happens when you flow with the intake on? I wondered how that effects the fuel distribution running into that flat edge at the bottom of the port.

[fordified]

Try to find a roush intake for Yates heads or similar small port Yates intake for a 9.2 deck. You you’ll need to mill the flanges a decent amount to get it to fit but it will fit the ports and be a hell of a lot better than any edelbrock Cleveland manifold.

[Steve.k]

With those stuffers or plates in the intake what happens when you flow with the intake on? I wondered how that effects the fuel distribution running into that flat edge at the bottom of the port.

This prostock head has intake epoxied also. They were trying to turn the flow to center of cylinder not fill the port. If you look on my flow sheet you will see the port volume filled is actually bigger than the ported head. The misconception was they were making port smaller. For what you want to accomplish a port job is more than adequate. Filling the head in my eyes is a waste of time unless your trying to accomplish what the prostock guys were.You have to realize the prostock motor was 343 cubes and was shifted at 9800 rpm.