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I have been reading this thread, ALL of it, and the issues seem so similar to my issues with my engine I put together on a fresh short block some ~20 years ago, in my '72 vert.....350/L98 heads, and a LT1 injection intake, heavily modded by a buddy of mine to allow HEI up top, where it is dry.....
Well, 3.5 months ago end of June the engine ran rough as a cob.....then it refused to crank....starter trying, but crank locked so pulled all the plugs, and sure enough water/coolent came out of the 2-4 plugs......dry on driver side.....so removed head and took to shop, cleaned and pressure tested....seems fine.....back together again.....went to fill radiator, and filled the OIL sump with water/coolant........pulled intake and everything under oil clean up to the heads.......drained pan and out came tons of water/oil/coolant, so pulled it outta the car with much reluctancy, machine shop, and so finally getting back together.....
so long a time because other life issues, including my arthritis attacks in my shoulders and hands making it very painful to work on the car, so many daze off nothing done.......
BUT, BTDT with that angle stuff, surfaces checked, FEL PRO gasket sets, and max Pair A NOYA on the assy work......
I wish I could help you. I had the exact same issues on a 427 big block before. I mean exact- smoke when it warmed up, but ran great. brown plugs, oil everywhere inside runners where it shouldnt be.
my solution was to get a new set of heads. I knew my heads had been milled quite a bit, so i opted for a fresh set of heads.
my machine shop advised me against machining the intake. he recommended pulling heads and having them machined if i did anything. his reasoning- if you machine an intake to fit heads, then you have heads and intake that can never be separated. if you machine the heads to fit a stock intake, you can use ANY intake should you ever want to change things,
if you truly suspect this mismatch in angle is your problem, i would be looking for a new set of heads.
I wish I could help you. I had the exact same issues on a 427 big block before. I mean exact- smoke when it warmed up, but ran great. brown plugs, oil everywhere inside runners where it shouldnt be.
my solution was to get a new set of heads. I knew my heads had been milled quite a bit, so i opted for a fresh set of heads.
my machine shop advised me against machining the intake. he recommended pulling heads and having them machined if i did anything. his reasoning- if you machine an intake to fit heads, then you have heads and intake that can never be separated. if you machine the heads to fit a stock intake, you can use ANY intake should you ever want to change things,
if you truly suspect this mismatch in angle is your problem, i would be looking for a new set of heads.
I never understood this logic. Unless it's some kind of rare intake it's a lot cheaper to buy an intake than a set of heads should you decide to change things down the road.
I never understood this logic. Unless it's some kind of rare intake it's a lot cheaper to buy an intake than a set of heads should you decide to change things down the road.
well in my case yes it was a tri power intake so pretty expensive. But I think the logic here is there is a problem with the heads. So if you mill the intake you make 2 problems to make it work. If you mill the heads and correct the issue you have zero problems.
well in my case yes it was a tri power intake so pretty expensive. But I think the logic here is there is a problem with the heads. So if you mill the intake you make 2 problems to make it work. If you mill the heads and correct the issue you have zero problems.
well in my case yes it was a tri power intake so pretty expensive. But I think the logic here is there is a problem with the heads. So if you mill the intake you make 2 problems to make it work. If you mill the heads and correct the issue you have zero problems.
I have run into the mani problems where
the heads were reported as "Shaved"
taken to a shop and found to be slanted.
I don't understand why getting the heads
"true" is such an issue?
not sure if you taking about my issue or the OPs. But in my case I’d run the intake on another motor for years with zero issue so I knew it was ok. Actually has been used with 4 different sets of heads over the years and only issues ever with 1 set.
in the OPs case he has tried multiple intakes and seems to arrive at the same conclusion with each.
Thanks for all the discussion. Very valid points all around. For my situation, I think I will try and get the manifold to fit. If this was a numbers matching LT1 and I was using the born with heads and the Winters aluminum intake. Yes I would pull the heads and correct the issue. But I'm using some donor 492s that are not born with the car ( I have the matching and dated 993s I pulled off) and yes the original intake and block, but the intake is nothing special, I can probably buy another one for $50-75. I've owned the car for 30 years, if and when I sell I will let the buyer know about the machined intake. So I will try this machining route first. If I need to pull the heads and get them all taken apart and milled, I think I will just go and buy some aluminum trick flows with the camel humps and paint them orange. Too much invested in the 492s.
As an update, I went to my machinist. Like everyone he is surprised I cannot get it to seal. Before milling the intake, he took off the splash shield on the bottom of the intake (he didn't like how the pan encroached near the runner, and asked me to take the gap readings again with the solder, and to bring him the solder strips because he wants to use his equipment to measure the compressions. If he decides to mill it, he says he will also clean up the drivers side and see if .120 gasket will then work the bolt holes. He plans on milling China wall as well. Says its on the tight side.
After laying the intake on the China wall. Rivets not an issue. Still have to recheck gaps.
...pulled intake and everything under oil clean up to the heads.......drained pan and out came tons of water/oil/coolant, so pulled it outta the car with much reluctancy, machine shop, and so finally getting back together.....
so long a time because other life issues, including my arthritis attacks in my shoulders and hands making it very painful to work on the car, so many daze off nothing done.......
BUT, BTDT with that angle stuff, surfaces checked, FEL PRO gasket sets, and max Pair A NOYA on the assy work......
MrVette. Sorry to hear about your ailments. Did the car run well before and for how long? Did you check the block for warpage before reinstalling heads? What thickness head gaskets? If its your intake, I hope my troubles will help you diagnose your problem.
While you are working to correct the manifold to head seal, you might consider adding a valley oil baffle. I have suffered leaky intake gaskets sucking oil in the past. The valley baffle stops oil from splashing up on the head to intake gasket interface. Might need to trim for the roller lifters but I have no experience there. This baffle also retaines the flat tappets in the event you have a valvetrain component failure. Think broken Rocker arm or pushrod for example. Lifters stay in the bores.
While you are working to correct the manifold to head seal, you might consider adding a valley oil baffle. I have suffered leaky intake gaskets sucking oil in the past. The valley baffle stops oil from splashing up on the head to intake gasket interface. Might need to trim for the roller lifters but I have no experience there. This baffle also retaines the flat tappets in the event you have a valvetrain component failure. Think broken Rocker arm or pushrod for example. Lifters stay in the bores.
