matching a intake to milled heads

[tcb3274]

Need a little help here.

I have a 383 that was zero decked to .005. The heads are aluminum Dart Conquest heads that started out at 72 cc's and were milled to 66 cc's by my head porter. My engine builder to my knowledge did not angle mill the top side of the head to fit the intake. The intake I was using was a EPS. I always had oil weeping out around the intake bolt holes. Now, I switched to a RPM intake. Appears the oil weeping has gone, but now it appears the engine is using oil. I think I may have a internal oil leak.

After the intake swap, my Dad took the car for a 70 mile cruise and it drank a quart and a half. No signs of oil lost. There is no signs of external oil leak. The only way to see that oil is being drank is by looking at the dipstick. There is no smoke or anything like that. No wet exhaust pipes, just the normal smut. Plugs look ok, maybe a little oil fouled. I believe the intake is not sealing at the bottom of the intake ports between the intake and the gasket.

Does anyone know how to calculate what needs to be cut off the intake to match up the ports better?

I would need help walking me through the process.

[tcb3274]

Wanted to add that I know the best solution is to angle mill the top side of the heads...however...since the engine is already running and in the car, it does not matter to me to mill the intake and permanently match it to the heads....99% never going to use another intake.

Thanks

[1972ho]

Have tried installing the intake without a gasket to see if there are any gaps,and if the China rail is not bottoming out out.

[cv67]

with the above. Have the same engine, same heads milled to 62 had to mill the intake (Team G) not one issue
Used Mr Gasket (106?) intake gasket

[cardo0]

Since you don't have record of how much was removed from heads and block you need to use the primative/old school method of using feeler gauges. Just set the intake down on the long block and slip in the feeler gauges - measure the ends also. You need to measure the surface angle also - protractor is needed as the angles need to match also.

Even the Chevy Power Manual has a table for this none of published information gonna help you w/o knowing how much has been removed already. IMHO if you had both surfaces cut you would want a measured cut rather than a calculated - verified angle to.

Good luck.

[tcb3274]

Thanks for the replies. I will have to take the intake off and clean up the area and do a few tests and measuring.

Sounds like quite a bit of figuring.....wondering if Im qualified to do this.

[1972ho]

Last time I tried to do it I took the intake to the machine shop 3 times and finally had to the block heads and and intake to the shop to get it right,But I found out that my block was not square so the shop had to figure it out.

[tcb3274]

Last time I tried to do it I took the intake to the machine shop 3 times and finally had to the block heads and and intake to the shop to get it right,But I found out that my block was not square so the shop had to figure it out.

I don't want to go down this route.....

I have a shop that says they can do the repair and a machinist that will be working with him, however, I would like to do the job myself if I can.

[ProPower engines]

Need a little help here.

I have a 383 that was zero decked to .005. The heads are aluminum Dart Conquest heads that started out at 72 cc's and were milled to 66 cc's by my head porter. My engine builder to my knowledge did not angle mill the top side of the head to fit the intake. The intake I was using was a EPS. I always had oil weeping out around the intake bolt holes. Now, I switched to a RPM intake. Appears the oil weeping has gone, but now it appears the engine is using oil. I think I may have a internal oil leak.

After the intake swap, my Dad took the car for a 70 mile cruise and it drank a quart and a half. No signs of oil lost. There is no signs of external oil leak. The only way to see that oil is being drank is by looking at the dipstick. There is no smoke or anything like that. No wet exhaust pipes, just the normal smut. Plugs look ok, maybe a little oil fouled. I believe the intake is not sealing at the bottom of the intake ports between the intake and the gasket.

Does anyone know how to calculate what needs to be cut off the intake to match up the ports better?

I would need help walking me through the process.

Well right off it looks like .040 was removed from your heads by the starting and finished chamber volumes you now have.
If you have a part number of what piston was used and if its 5.7 or 6" rods just in case you don't know you can get real close if you used a stock block as most stock block we see here need about .030 off the decks to get the piston to 0 deck so that said you probably have a total of .070 between the block and heads to correct.
Here is an example of the math used,

A positive example: RB (413, 440) face angle is 10° positive.
.707 ÷ SIN(35) = .707 ÷ .5736 = 1.2326, so remove .0123” for each .010”.
A negative example: LA (340, 360) face angle is 3° negative.
.707 ÷ SIN(48) = .707 ÷ .7431 = .9514, so remove .0095” for each .010”.

Basically its .013 off both sides of the intake for every .010 removed from the block/heads or .091 per intake face
In a perfect world and top quality parts to work with that have no machining errors and location tolerances

Since you have no exh. cross over in the intake to deal with find the thinnest intake gaskets that match the ports and glue them to the heads being careful to get perfect port alignment.
After you machine the intake use some black paint to outline the ports of the gaskets then set the intake in place wait a minute for the paint to transfer then check the port to gasket alignment.
You may need to take more off to get it perfect but at this point depending on how the ports are laid out in the heads you have and how nice of condition the intake you want to use is. Just saying in the last 10 years or so I have not seen any intake out of the box that fit even close.


If you have the ability to machine the intake yourself start small or short of the math total and sneak up to the finished amount needed to get it perfect.

[tcb3274]

Need a little help here.

I have a 383 that was zero decked to .005. The heads are aluminum Dart Conquest heads that started out at 72 cc's and were milled to 66 cc's by my head porter. My engine builder to my knowledge did not angle mill the top side of the head to fit the intake. The intake I was using was a EPS. I always had oil weeping out around the intake bolt holes. Now, I switched to a RPM intake. Appears the oil weeping has gone, but now it appears the engine is using oil. I think I may have a internal oil leak.

After the intake swap, my Dad took the car for a 70 mile cruise and it drank a quart and a half. No signs of oil lost. There is no signs of external oil leak. The only way to see that oil is being drank is by looking at the dipstick. There is no smoke or anything like that. No wet exhaust pipes, just the normal smut. Plugs look ok, maybe a little oil fouled. I believe the intake is not sealing at the bottom of the intake ports between the intake and the gasket.

Does anyone know how to calculate what needs to be cut off the intake to match up the ports better?

I would need help walking me through the process.

Well right off it looks like .040 was removed from your heads by the starting and finished chamber volumes you now have.
If you have a part number of what piston was used and if its 5.7 or 6" rods just in case you don't know you can get real close if you used a stock block as most stock block we see here need about .030 off the decks to get the piston to 0 deck so that said you probably have a total of .070 between the block and heads to correct.
Here is an example of the math used,

A positive example: RB (413, 440) face angle is 10° positive.
.707 ÷ SIN(35) = .707 ÷ .5736 = 1.2326, so remove .0123” for each .010”.
A negative example: LA (340, 360) face angle is 3° negative.
.707 ÷ SIN(48) = .707 ÷ .7431 = .9514, so remove .0095” for each .010”.

Basically its .013 off both sides of the intake for every .010 removed from the block/heads or .091 per intake face
In a perfect world and top quality parts to work with that have no machining errors and location tolerances

Since you have no exh. cross over in the intake to deal with find the thinnest intake gaskets that match the ports and glue them to the heads being careful to get perfect port alignment.
After you machine the intake use some black paint to outline the ports of the gaskets then set the intake in place wait a minute for the paint to transfer then check the port to gasket alignment.
You may need to take more off to get it perfect but at this point depending on how the ports are laid out in the heads you have and how nice of condition the intake you want to use is. Just saying in the last 10 years or so I have not seen any intake out of the box that fit even close.


If you have the ability to machine the intake yourself start small or short of the math total and sneak up to the finished amount needed to get it perfect.

Thanks for the detailed reply...Im going to have to read that several times to digest!