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Discussion Starter #1
Read all the head threads and still confused. I am pulling my van engine due to a rod knock so figured upgrade while I am at it. Will install ARP head and main studs, new rod bolts of course, gear drive and a RV grind cam from my local grinder. I see some recommend sticking with the 6.2 heads, others say 6.5 and 91-93 vintage? So, what is the deal, what numbers and is it worth it? Also, whatever head I use, it porting worth it and going oversize on valves. This will be an N/A engine.

Thanks alot guys, learning lots already.
 

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Hey turbovanman,

Head studs are a good addition to the turbo motors, and probably not a bad idea on any 6.2 or 6.5.
I've read more than a few posts where these blocks have a tendency to pull the threads outta the deck on certain holes.
Studs should reduce that possibility.

As far as heads go, I believe the #567 castings are better than the earlier years, as far as being less crack prone.
I've found them on '92 6.2's and 6.5's, both.
I think they were on most of the 6.5's clear up through
'98, fitted with different pre-cup designs.

99% of the guys will tell ya NOT to go oversize on the valves. GM tried that on the '82 motors and quickly abandoned the practice. Definitely increases the possibility of cracking between the seats, even on the better heads.
On a N/A motor, the stock valve size works fine.

Probably the best bet would be concentrate on air flow with a low restriction "J" code intake, and cool ram-air through the grille.
Run as big a dual exhaust system as you can fit with a crossover, and add fuel to match.

You'll find there's a TON of great info here, just gotta search it out. LOTS of knowledgable folks here!
Check out the FAQ.

Mike
 

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Discussion Starter #3
Thanks for the info, funny thing is, I have checked, spent a few hours searching, saw about the intake manifold, use a good air filter setup and pump adjustment, gears instead of a chain although I can't help but wonder if nobody makes a good chain? but nothing really concrete on heads, porting etc. I am on 3 Turbo Mopar forums so I know to search before asking, I am a mod on 2 of them, lol! :p:

Yeah, will spring for headers, a good 2 1/2 dual exhaust with an X-pipe, probably go with Flowmaster Super40 mufflers, they worked great on my turbo Mini. I am also going to try to find a serpentine belt setup and retrofit of a later model truck, that fan belt system is a friggin joke-Censored

So far, lots of good info, I guess just need the head story and I am done. ):h
 

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Discussion Starter #4
These are the casting numbers off the head-

14057299 and there off a mid 90's 6.5L. Any good?
 

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I recall the #299 heads being discussed............just can't remember where, or if the opinion was good/bad.
There was mention of a mid-late '90's head with revised cooling passages. Not sure if #299's are the ones, though.

I'm a little leary of aftermarket timing chains for 6.2-6.5's.
The ones I've looked at aren't true roller chains, they're split rollers. (read CHEAP) My 6.2 recently had a chain and gearset installed, and it is a true roller..................but then, again the previous owner's brother owned the Chevrolet dealership, so it was probably an OEM replacement. Avon used to supply the OEM, I believe.

Yeah, I'd go with a serpentine set up over the V-belt anyday. Nothing like overtaxing a PS pump with a hydroboost, and then running with about 1/3 belt contact on the pump pulley!
Believe me, EVERY 6.2 I've ever owned squalls the belts relentlessly! LOL!
You should be OK going serpentine on your '86, as it should have o-ring type PS hoses to mate up with the later pumps. Just grab the water pump with the new set up.
I believe serpentine setup uses reverse rotation WP's.

Good luck!
Mike
 

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Discussion Starter #6
Thanks, hopefully more people can chime in about the heads.

Yep, knew about the waterpump, :D
 

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86 heads were fine, bottom line is build a pressure testing plate to make sure there are no coolant leaks and put it back together. Gasket matching wouldn't hurt, but I don't think that headers are worth the trouble. Run dual 2.5 inch pipes with free flowing mufflers, j series intake and open up the air cleaner with possible ram air, turn up the injection pump and advance timing slightly. Gear drives are over rated imo, timing chains do get some slack, but I have never seen one out of spec. factory tolerance is 3/4 inch of slop. Factory chain sets are true roller, most aftermarket ones are not.
Heads after 92 have a different angle for the injectors, requiring different injection lines or tweaking stock lines and abandoning stock hold downs. Later model heads with this different injector angle benefitted from reduced smoke, but not much in the power dept. All of the heads will crack between the valves if worked hard and coolant temps get hot, but most of the cracks are only surface and usually occur on the end cylinders. Pressure test for piece of mind and do the repair with a reamer and press in valve guides in the water passage if a crack does leak. Only heads that should be junked for cracks are if they are cracked in other places other than between the valves.
 

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Discussion Starter #8
So your honest opinon is just stick with the stock heads. What about porting them-that has to help. The 6.5 heads do have the cast rockers so I will just use those instead, :D

Well not doing the gear drive saves me $500 so thats cool, can put that into the porting.

Again, thanks everyone, sounds like a have a solid plan on which to work with.
 

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Because of the rpm limit on these engines, the head porting may not be of much benefit. Generally, these heads flow sufficient air at the rpm the engine will turn without serious porting. It won't hurt to "clean up" the ports but much more than that is probably overkill. On an engine with functioning EGR, the porting and polishing would soon be covered up with oil residue, defeating the purpose. Because we spend so much time at the lower end of the rpm range, I doubt you'd notice the port/polish much. Race truck, different story.
 

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Discussion Starter #10
Great post. My thinking is there is no throttle blade so the engine is always pulling as much air as it needs, obviously air restrictions limit that, so if a port job is done, the engine at any RPM is now taking in X amount more air, add fuel and bingo, more power, :D
 
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