Scored some heads, motor always stalls... Cure ?

[Gohot]

Last week I responded to a add on Craigslist for some "J" heads. The price was cheap enough, so I took a ride some fifty miles over to see them. I encountered a Drag racer fella named Dave. Seems he has a store or outlet in Charlotte NC. and is very involved in Drag racing, though it also appears he has turned to the dark side with GM stuff. Still he races front engine Nostalgia Rails.

In the course of conversation, a comment was made about my motor always dying when I came to a stop or that and using the brakes, leading me to think it was a vacuum leak. My thoughts went towards a power booster leak........ but whatever it would run ok at rpm's above 1,000 or so. He suggested the locating pin in the rear of the block as the likely culprit, and thinking back, I have no doubt it was a likely suspect. I had changed all the intake gaskets just recently as I had gotten a Eddy Performer. I sprayed Coppercoat on the metal gaskets as a precautionary hoping for a little extra sealing. Not good....... it seams to have been corrupted by antifreeze and turned to a non-hardening mushy substance. Anyway, I had fluid loss, thus the teardown. Ok I cleaned everything back to shiny, the deck, the web front and rear, the manifold completely, and black silicone the Felpro gasket set onto the block. I let them set to cure up a bit as they were cork.

After an hour or so I came back to the install and proceeded to mount the Eddy back on the motor. Right off the start it was hard to locate the locating rollpin. I farted around for a bit and it felt as though it had aligned....... or it sort'a felt like it did. Upon reflection, I doubt that was the case. So I now have this rollpin problem and a vacuum leak .....(I think)  I'm going to try a vacuum gauge first, and then determine if it is in fact leaking....  I'll just have to search up baseline Vacuum in my FSM manual.  Another thing that leads me to think Vacuum is that it seems to have leaned out, in fact runs hot sometimes on the highway, or hotter than it used to. I have had this motor running tits previously, no stalls, perfect idle tuning with the Edelbrock 1406 carb (600cfm) which ran rich previously. Enough so that I was thinking of Restrictors and the Calibration kit from Edelbrock. So the lean symptom fits I believe.

So the next thing was these heads I got..... some real nice 'J' heads. Nice valves, nice seats, and nice double wound springs. I mentioned the overheating slightly, well I also got a new water pump too.
I was thinking of getting a complete gasket kit and putting the heads on.... some say don't others say they ought to run ok on bottom and scream on top. I have Hooker 2 1/2's and the Eddy Performer & Carb along with a new double row chain currently, and running a GM modual conversion, all on a 318
I know this is perhaps iffy with the motor combo, at least without putting in Keith Black 167's and some cam in the 450's to 480's but one thing going for me is that this is a 2x4 RC, so the drive train is considerably easier on the motors HP and Torque patterns over a 4x4 combo.

Anyways, I guess I'll have my Daughter get me some Felpro's, and entire gasket kit, since she works at NAPA and avoid having to get a top end kit or a bottom end kit or partial kits, instead just get the whole dang thing and use what I need and save the rest. 
So have any of you done something similar and ran J heads on a 318?  these are also 2.02's which seems a bit too big under the circumstances as well. I have to change the gaskets, stop the leak, so I would like to use them if it was ant HP increase ? Any thoughts ........ 

[Gohot]

OH YEA, PS....... I was also thinking Eddy Air Gap with these heads. The Performer is likely too small with port match and runners

[Gohot]

Further on..........Well again I replace the gaskets with Felpro Performance  composite intake gaskets. I follow the advice of not using the cork and use silicone instead, liberally. I let it dry a day, piece still leaks....... OFF comes the Eddy's and on goes the stock freshly painted and detailed stock manifold, with the two barrel. I have these nice heads now, a manifold and carb topped with a Mopar air cleaner. I really think stock will find more use to me than Hi-Po..... 

But now the two barrel is leaking, flooding so I guess I
'll be taking it apart, it's a 74 year carb, so it's not to complicated with acc. junk everywhere like the slow burn it replaces.