Blew a head gasket on rebuilt 383.

[Hammond68]

5000-6000 on it. I bought it of an older man. He may have used his own torque sequence, thought he didn't need a torque wrench, re used bolts who knows.
Anyhow, going vortec 062 now. Compression will be 10.47 to 1.64 cc chamber on on flat tops with 5 cc valve relief. Pistons are .025 in the hole. Comp 280 magnum cam. Comp cams recommend 9.3 to 10.8. Think I'm going to high?
Yes, I know I'll need an intake. Any advice would of course be appreciated. You guys are great,every time I need help spending my money y'all come running.

[rcazwillis]

Are you daily driving it? Do you mind putting better fuel in it? You may have to drop the timing back a bit. You can drop the ratio a bit with a thicker gasket. It will hurt the quench some.

That combination will be nice if you are willing to manage it after the fact. I would run premium in it and set the timing back to about 28-30 all in at 2500.

Do you have valve springs for that much cam? What intake will you use?

[Hammond68]

I'll try that timing curve when I get there. Haven't picked up the heads yet. Found on fb marketplace. Stage 3 .520 lift clearance. Should have good springs. Came from a machinist 5 or 6 months ago. Guy went ls swap instead. I'll have my machinist look them over but that will be after the purchase .

[rcazwillis]

Best indicator on heads will be machined valve guides where the springs sit. The heads are cast with valve guides that are too big around for most good springs. To fit good springs, the outside diameter of the valve guide is cut down. Same process opens up the diameter of the spring seat. If you don't see that, I would ask some more questions. Bee Hive shaped springs would also be a good sign.

[Redneck Rydes]

A really good intake would be a Vortec air gap,I have used a few and like the performance curve,if you are going to use the truck for pulling and just putting around,just use a nice 2 plane intake

[rcazwillis]

Is the air gap not a dual plane?

[siggyfreud]

Originally Posted by rcazwillis

Is the air gap not a dual plane?

The Performer RPM Vortec airgap is a dual plane manifold.

[Redneck Rydes]

The air gap is a 2 plane,but if you run a lower style 2 plane like the old 2101 style the rpm range is a little different

[AussieinNC]

Suggest you make sure you check the block deck surface is perfectly flat....

Also, check each head bolt hole for crowning around the hole....

Chase each hole thread with a new correct pitch tap...

Also for cracking of the deck surface radially from each bolt hole....I have witnessed cracks develop from oil being in the bolt hole and the bolt being torqued down against the hydraulic pressure....

If you can afford them, now is the time to install head studs and hardened washers and nuts...otherwise, use NEW head bolts.

As far as torque specs and sequence...start in center, work in circle and move up in 10 lb increments up to spec. Leave overnight !

"Then back them off half turn and re torque to spec...again coming up in 10 lb increments."

[rcazwillis]

Originally Posted by Redneck Rydes

The air gap is a 2 plane,but if you run a lower style 2 plane like the old 2101 style the rpm range is a little different

Got it. I did not understand the point you were making. The lower rise manifolds will have an operating range that tops at 5000 - 5500. The Airgap is higher because of the longer runners.

[Redneck Rydes]

Thats it!

[GASoline71]

Small Blcok Chevy head bolts can be reused if reinstalled properly. If you are installing aluminum heads or are thinking of some CR of 12:1 I'd use head studs. But a stock iron Vortec head and 10:1 CR will be just fine with stock head bolts.

Your stock torque converter is gonna hate that camshaft. You'll probably need a minimum uf a 2,500 stall. If you have high gears in the rear end (numerically low), it will be a bit doggish off the line.

Gary

[Big Kev-O]

When you install that Edlebrock intake onto those Vortec heads I would not use the gasket Edlebrock recommends. They get pinched down into the lifter valley. "The problem originates where the bottom of the intake port to the intake manifold creates a diverging angle near the bottom of the port. This reduces the clamp load on the gasket and after multiple heat cycles the gasket eventually allows engine vacuum to pull oil directly into the intake port".

I started with the recommended Edlebrock gaskets then some Fel-Pro 1255, both sucked oil from lifter valley and eventually coolant from rear ports. Then after much research I tried the gasket from the Fel-Pro SFLMS98000T kit. They have a steel frame and dowels to keep them in place durring install. They are only sold in the kit but well wort the cost. Only other solution is machining the manifold.

[rcazwillis]

Originally Posted by Big Kev-O

When you install that Edlebrock intake onto those Vortec heads I would not use the gasket Edlebrock recommends. They get pinched down into the lifter valley. "The problem originates where the bottom of the intake port to the intake manifold creates a diverging angle near the bottom of the port. This reduces the clamp load on the gasket and after multiple heat cycles the gasket eventually allows engine vacuum to pull oil directly into the intake port".

I started with the recommended Edlebrock gaskets then some Fel-Pro 1255, both sucked oil from lifter valley and eventually coolant from rear ports. Then after much research I tried the gasket from the Fel-Pro SFLMS98000T kit. They have a steel frame and dowels to keep them in place durring install. They are only sold in the kit but well wort the cost. Only other solution is machining the manifold.

How did you identify this issue? Oil consumption? Did you see signs of it in the intake runner of the head? I have a vortec burning oil. It was a 12k mile engine that I fully expected to be good. Bearings, etc in great shape. Did not look at rings etc. I am wondering if I might have this issue.

[GASoline71]

Originally Posted by Big Kev-O

I started with the recommended Edlebrock gaskets then some Fel-Pro 1255, both sucked oil from lifter valley and eventually coolant from rear ports. Then after much research I tried the gasket from the Fel-Pro SFLMS98000T kit. They have a steel frame and dowels to keep them in place durring install. They are only sold in the kit but well wort the cost. Only other solution is machining the manifold.

It's weird how some work and some don't. I had the exact opposite problem with a standard bolt pattern RPM Air Gap bolted to regular Chevy heads. The Fel-pro "perma-torque" gaskets didn't seal the bottom of the intake runners at all and I sucked oil. I switched them out to the recommended gaskets from Edelbrock and the problem is fixed.

Gary

[Big Kev-O]

Originally Posted by rcazwillis

How did you identify this issue? Oil consumption? Did you see signs of it in the intake runner of the head? I have a vortec burning oil. It was a 12k mile engine that I fully expected to be good. Bearings, etc in great shape. Did not look at rings etc. I am wondering if I might have this issue.

It idle rpm started to increase despite closing throttle blades, lots of smoking and super rough when in drive at a stop. I blamed the carb and got FiTech EFI , changed plugs and it ran good for one day. Couple plugs were soaked in wet oil. After reading tons of complaints about the vortex heads and aftermarket aluminum intakes. Pulled the intake and found this.
Posted via Mobile Device

[rcazwillis]

Originally Posted by Big Kev-O

It idle rpm started to increase despite closing throttle blades, lots of smoking and super rough when in drive at a stop. I blamed the carb and got FiTech EFI , changed plugs and it ran good for one day. Couple plugs were soaked in wet oil. After reading tons of complaints about the vortex heads and aftermarket aluminum intakes. Pulled the intake and found this.
Posted via Mobile Device

I am thinking my issue is rings, not intake. It idles fine, there is a slight about of blow by which increases slightly as RPMs increase. Thinking there would be a vacuum on the crank case if intake gasket was sucking oil.

Thanks for the great pic.

[Redneck Rydes]

I have never been a real fan of the "new vortec intake bolt pattern,we never had these problems with the old 12 bolt style intake,when they got rid of the inner bolts,there was no clamping force for the inner intake runners,obviously it has worked since 96/but bad gaskets and milling blocks and heads can cause a problem.