Heads ??

['90Vert]

I recently put in a turbo. I just started having a rough idle and sweet smelling exhaust. This might be the problem........

['90Vert]

I have gt40 heads that were put on about 10k miles ago (but not by me) with a felpro 1011 gasket and ARP bolts - I’m surpriseed it didn’t hold.

The car has been conservatively tuned for the turbo and has 390 HP (at wheels with Mustang Dyno) with 11 pounds of boost.

Should I use ARP bolts or studs to put it back together? I’ve heard many times that studs are stronger, but I’m having a hard time understand how/why?

What gasket should I use?

While the heads are off I’m thinking about having them ported and also replacing the stamped stock rockers with 1.6 roller rockers? On the other hand I’m not really looking for more HP, and If i was I could just turn up the boost more...... I’m trying to stay at a safe conservative limit for the stock 302 block. Port or not? Roller Rockers or not?

[onjacks]

how much boost? stock style heads dont like over 10lbs. they lift and spit gaskets. ALWAYS use studs with any power adder.

[robert]

Might want to check tune after fixing the gaskets.
Bolts not the issue, you rather change gaskets than a piston or block.
Try MLS or 9333pt1
my .02c G/L

['90Vert]

how much boost? stock style heads dont like over 10lbs. they lift and spit gaskets. ALWAYS use studs with any power adder.

It's at 11 pounds.....

What makes studs stronger then bolts? I'm not saying there not, just asking why?

[Chas_svo]

Or more than likely, the bolts weren't retightened after a heat cycle or two. Go with studs, and follow the instructions. If you're tune is off, no gasket or stud is going to fix that, but my bet is the bolts were retightened.

And yes, port the heads and add rollers.

[onjacks]

with $$ invested in porting your better off selling the heads and investing in some aluminium trickflows @$1200 for the pair.

No more hg trouble and more power w less boost.

[Chas_svo]

It's at 11 pounds.....

What makes studs stronger then bolts? I'm not saying there not, just asking why?

Torque Efficiency
*
During engine assembly or maintenance, a bolt must be installed by torqueing it into place. Due to the head bolt’s design, it has to be rotated into its slot in order to engage the threads and secure it into place. This process creates both twisting force and a vertical clamping force, which means that when the cylinders within the engine’s combustion chamber begin accumulating load, the bolt will both stretch and twist. Because the bolt has to react to two different forces simultaneously, its capacity to secure the head is slightly reduced and it forms a less reliable seal in high-powered engines.
*
By contrast, a head stud can be tightened into place without any direct clamping force applied through the tightening. A stud can be threaded into a slot up to “finger tightness,” or the degree to which it would be tightened by hand. Afterward, the cylinder head is installed and a nut is torqued into place against the stud. The nut torque provides the clamping force, rather than the torque of the fastener itself, and the rotational force is avoided entirely. Because the stud is torqued from a relaxed state, the pressure from the nut will make it stretch only along the vertical axis without a concurrent twisting load. The result is a more evenly distributed and accurate torque load compared to that of the head bolt. This ultimately translates into higher reliability and a lower chance of head gasket failure.


And as far as cost, you might be ahead to buy heads if you are going to pay someone to port. It's all labor.