Figured I would throw this out there..Mentioned before I may put in a 383 stroker in my 73....Presently have a 350 .040 over in there now that runs very good, but does burn some oil....

Was thinking maybe using the pro comp heads I have on my 350.....They are 190cc 64 cc..2:02....

Anybody know the going rate to maybe clean these up and do some port work on these heads? I'm hearing the castings on these pro comps are not bad and they respond well to some porting...
I figure on taking every part off my 350 that I can use, except of course the cam....

 

Head porting is expensive. You might contact pro comp. I have AFR 210 heads with 2.08/1.60 valves. They are the Race ready version and I decided that I wanted the full CNC and up the intake valve size. I contacted AFR and the price was $900 at the time plus what ever type of intake valves I decided on. So for something like $ 1200 total bucks I was going get 2.10 intake valves and an additional 22 CFM. My heads would have been opened up to something like 221 CC.

Value for return is very low. So I thought that it was better to just buy brand new larger CC heads and sell mine.

I ended up just refurbishing my own P&P and doing some machining to increase the oil return.

I also looked closely at the AFR CFM and valve lift graphs. The max CFM is up over the .600 inch lift through .700 inches. So instead of porting why not just keep the valve open for the longest time in the higher CFM? In quality engine simulation software you can input the lobe ramps and corresponding number of degrees of rotation that the valve has at all lift points. Not just the .050 lift duration, but clear out to over .700 inches if your cam and rocker ratio can do it. So I had comp cams make me a solid roller cam with mid .600 lifts using 1.6 ratio rockers and a cam for my 427 SBC lifting the valves .685 and .714 using 1.7 ratio

 

Baisic porting is not very hard to do. I did porting on my Dart heads using a porting book by David Vizzard as a guide. It involved skinning down valve bosses, cleaning up port exits and slightly straightening ports primarily.
It is labor intensive and I wouldn’t even attempt it with a Dremel tool. Die grinders are cheap at Lowe’s then all you need is some bits.

Valve lift duration can do plenty as well as gkull points out. Also narrowing the LSA gives good returns on torque in the mid range. On a 383 think 107 or 106 vs the off the shelf 110 or 112.

 

Electric die grinder from harbor freight. I use mine on iron bbc ports. Aluminum is waaaaay easier to port. BUT-Dont buy cutters from harbor freight.

 

Or anything else that's supposed to be sharp or involved in cutting including drill bits, saw blades, etc. I found out the hard way with sawzall blades. Just about as sharp on the smooth side as the side with teeth...

 

If done right its never cheap but worth it. That is an art that takes years to learn. Are you planning on doing this or paying someone?

If its the latter make sure they are doing it not farming it out or having some hourly guy doing it. If it costs a few more bux to get a port or 2 flowed before and after to see what was done, insist. Pretty ports dont mean they work (in fact rolling out a port isnt even necessary).

Its getting tough to find these guys anymore as anyone who really knows what they are doing will probably want 750-1200 to do a set give or take. They will probably want to do the valve job too as the wrong one can hurt performance. All depends what you expect & budget


Keep us posted.

 

I have seen many heads ruined from porting by someone who didn't know what they were doing. The valve job is extremely important also. There can be huge amounts of airflow lost or found here!

Mike

 

If a guy wants to find significant amounts of additional flow then yes it's gonna take someone who is proficient at it.
Porting does not mean just simply hogging out the port to make it bigger. That in fact will likely result in loss of flow at every RPM with possibly the exception of the very end of the RPM range.

This book will give you a really good basis on which to port with some decent results.

I used the basics from this book and ported a 1985 Toyota corolla head when I had it off and gained 4 MPG (previously 40 mpg, after porting 44 mpg) and about 5.5 HP. Original engine 68HP. So even a novice like me can have some positive results.

If you want to try you'll see that there is a simple logic to getting better flow. Beyond that it will take much more experience and flow testing to find more flow.

 

On the 383" retro-hyd-roller pump-gas platform those head will easily produce 450+ HP, and with some very minor bowl work, you'll see 500 HP.

Been there numerous times with these particular castings! Have many sets out for over 10 years now with NO issues whatsoever!

Thanks, Gary in N.Y.

P.S. I would just add this with respect to "real" porting, the "easiest" areas on the castings to port yield the least amount of gain on the end result!!

 

Absolutely! The seat and the areas closest to it in the port and chamber are the most critical. Small changes here can make large differences in airflow and the quality of the airflow.

Mike

 

As far as the cost, if its that much, up to 1,200 I would just probably get a set of new heads and sell these....My nephew has a set of pro maxx heads on his supercharged sbc ....They were only around 900 dollars and he is very happy with them...

 

Pro Comp are pretty hood castings. Their valves, springs, etc are about 5 cents a lb.

 

Yeah they are bad, give them to me and get a deal on some AFRs from TPI421 vette.

zrc not every application needs an all out gonzo job. It can be expensive or not depending; meaning a 300 cfm head isnt necessarily the best one.

Less work in the right places> lots of chopping everywhere & a big flow#

 

There was a 496 for sale by me. Pro comp intake valve head came off at IDLE. Still enough to wreck his block. Buy bare procomp castings. Then you wont be tempted to run their valves.

 

Back in the day I ported a bunch of heads most were cast iron,I think I still taste it when I hear a die grinder.lol most I had to put tubes in to make any improvement.. at some point I may do the pro comps on my car but I'm not looking forward to it.. reading a book won't make you a brain surgeon keep that in the back of your mind..there are still guys doing porting work.one place I can recommend if they are still there is in Maryland it's Ladd's porting.he's as good as they come.

 

If you have not done it many times I do not recommend porting a new set of heads. These days with computer simulation and wet flow tech it is not really that much of a gain....especially since casting technology has improved tremendously.
I am a fan of Dart.......they have tightened up quality and casting and redesigned their Platinum Pro 1 heads some 8-9 years ago with wet flow technology. My last set that went on my own engine were amazing on how well they were machined. The valve job lapped into a set of out of box valves perfectly and the seat to bowl transition was out of sight....
I saw not real reason to port on these......and the finished product runs pretty damn hard.....
But.......real gains can be made by sending fresh heads to a accomplished R&D facility like Modern cylinder head or M2. When CNC'd, the port shape is actually altered and size increased in most cases.....these changes are huge and yield big gains.....but remember...these port programs have been researched to the nines and thousands of dollars spent on development invested.
Spending more money on a Dart or AFR out of the box is a better deal in my eyes than porting a set of $700 castings.......
I have not heard terrible things about the Pro Comp stuff but I just can't bring myself to use them on anything.
This is my opinion and it is supported by a lot of trial, error and builds....
If you are just bored and want to tinker....that is fine too......but I would rather spend my time on other things......like optimizing the combo and buying a high quality carb......
Good luck to whatever you decide.....

Jebby

 

If and when I do the 383 stroker I will just go with a new set of aluminum heads and a nice cam to match.....Will most likely put the pro comps up for sale on Craig's list or something...I have not had a problem with them since I put them on about 8,000 miles ago..

 

I would not port them yourself, odds are you'll do more damage then good. I would send them out for some light porting, bowl work and a GOOD valve job...They are probably going to need valve guides anyway. A light clean up mill and some good valve springs, you'll have 500hp capable heads for not a lot of money.