Sorry Alex, I was asking stock diff gearing, as in 3.54.

Thanks

 

No, that's my bad. Thought I had mentioned it but didn't double check myself. Yep, stock gearing I'd like to go to like a 4.56 on 315/85r16s though.

 

Just aligning the intake gaskets might do more than porting. The insides are rough, so some gains from polishing. Maybe filing or grinding the exhaust headers?!




Even sports cars see bigger gains by going to Individual Throttle Bodies (ITBs) and ditching the single factory throttle body.



There is room to grind out space for larger valves.

New cam is easiest, cheapest, surest power gains of all, though.

Coil-On-Plug coming in a close second.

 

Got the heads, and parts for cleaning and painting to the shop. He checked to make sure they were flat, and vacuum tested them as well. Both checked out good.

He is a good guy, and didn't disparage my polishing job, so that made me happy. Stopped at Eastwood to exchange the Calyx Manifold Dressing for manifold paint and the guy there says the shop has a good reputation. Also, got a longer mandrel to polish the exhaust manifolds, that he says will not noodle.

In the shops opinion the block had expanded and stretched the bolts. The warmest it has been since rebuild is 226 to my knowledge. Maybe it overheated when first installed. Would that temp distort the stretch bolts, and cause the heads to leak? Anyway, it was leaking in a couple of places not just where the coolant was bubbling out. In the rear it was leaking oil.

His advice was to stay away from the ARP Studs, and use the stretch bolts. He gave me a little tool to track the degrees you have torqued. He thought I was paranoid not wanting to do the 90 degree turns in favor of just torque on the ARP studs. Along with Turner he cautioned they are too much of a good thing and could rip the threads out of the block. What do you guys think? I am leaning towards the ARP Studs still. I watch my temps religiously now.

Someone had dented a cylinder head where the valve cover mates prying it off with a screwdriver. Instead of selling me a big costly fix he told me to JB Weld it and sand it true. That made me happy.

He knows his stuff, and there were some really nice old cars in there so I trust they can deal with this job easy. They are going to get my intakes, brackets down to bare metal and paint them for me, too.

Excited to get them back.

 

I doubt the heat stretched the bolts. I don't recall the stretch rate of aluminum, but I know that steel expands .001", per inch of material, per hundred degrees. You're already running from 0*f (or colder) to 200*f when the weather is cold. Another even 80*f isn't going to be make or break.

The ARP studs.... If you're not planning to have the heads off any time soon, I'd stick to bolts. I like studs for re-usability, but I don't run them on my Disco because of a: the affordability if bolts, and b: they're not a weak point. Between de-threading a block and breaking a bolt, I'd break a bolt 10 days out of 10.

 

 

 

...headers

 

Seconding headers.

 

I went with the ARP studs and recommend them, however, ARP listed only 70 ft pounds of torque for our 4.6 motors, whereas the Atlantic youtube video used 85 ft pounds on them.

i used their precision torque grease and installed them at 81 ft pounds. My gut feel was that 85 ft pounds was too close to the limits of the aluminum block threads.

No problems at 81. JB Weld on a head?! Ummm...