Morning all
I am getting ready to get the heads done and wanted to confirm some things first. I am NOT building a strip truck but want something with good performance and yet still usable day to day. No premium gas!! Sheesh, not at these prices. As for the ?, they are asking what stage porting / polishing am I looking for. also I have seen mentioned in here the need for changing exhaust valve sizes. I will probably have the heads completely rebuilt, new valves, springs etc. Currently the heads are C8AE-H. Comments?

There is NO replacement for experience. Why rebuild the wheel if you don't have to.

 

'stage' eh?
'stage' of porting scares me.
stage 2 at x shop may be a simple clean up at y shop.
No where are stages of porting defined for all shops to use as a guide.
Stage of porting is as vauge and misleading at 1/2 - 3/4 race cams of the 60's.
It really means nothing to have a stage # of porting.
Polishing is not something that I'd have done to a set of heads. A super smooth surface will not flow as well as 'regular' finished surface.
A super smooth surface will hace the air/fuel mixture cling to it.
A regular surface will litterally tumble the air along it's surface, makeing sort of frictionless air gap effect, allowing the air inthe port to move much less restricted.
I'm no expert on areo/fluid dynamics, so I barely grasp the idea myself, but I'm sure if you do some probing around you'll find some usefull information on why not to polish the runners in your heads.
Any set of high dollar heads I've seen from TEA, Bennet, EdCurtis that I've had my hands on were far from polished.
Some shops may consider stage of porting simply how much material they remove from the runner, and that is definatly not where the power is extracted from. Escpcially not if the intake is not matched.

If you are building a truck - truck, not a race truck, I would not have them open the runners any more than necessary to match the intake.
I would have them flat milled, maybe look for 9.0-9.2 compression.
I would have a 5 angle valve job.
I would have the combustion chamber worked over a little, in that I'd have them unshroud the valve, and the spark plug.
I would have the bowls blended(radius work) and that would be all.
That is where all the flow is gonna come from on a typical set of heads.
Hogging out the runners would be a waste on money in my opinion... not to mention very time consuming iron heads.

Hope that helps.

 

First off, what amount of cash are you planning to spend? Considering you are not out for race performance, just ask them to replace the guides, the seats, a three angle valve job with replacement valves. You will also need springs, retainers and keepers. Your cost should be $350-$400.

Now, if you go with the oversize valves, then you will need SS valves, plus the porting/polishing, you will be upwards of $600+

Just $.02 --Mike

 

Just my honest opinion....

If your not really going Hi perf... I would just have a port match done ..both intake and exaust.... and a matched set of gaskets.. 3 angle valve job will be fine...

Have them check the spring pressures and shim if needed.. and new guides..

I would also go with PC seals on the intake valves..

But for Ocassional light to light...Thats all you should need to last..
And of course hardend seats are always nice.. JMO...Russ Good Luck!

 

Thanks guys but what about all I have read about the 1.66 Exh. valve being the way to go? Comments. By the by, I got a 390 today from the yard and took it apart this evening. finsih up tomorrow but the rods and the crank look good and the block is standard. The 390 pistons look exactly like the ones out of the 360 expect for some cosmetic things. Short skirt, overall length etc. with the 390's being marked as 410's. The 390 rods are substantially heavier looking and shorter as well. My question is this...can I use the pistons out of the 360, already .030 over, and the rods from the 390? I am assuming the wrist pins and such are the same. The ones out of the 360 look to be in better shape.