PRO COMP ALUMINUM HEADS

Originally Posted by frdnut

How did you arrive at that conclusion?...Big Joe did not compare the vic jrs to pro comps he compared them to AFR 205s...Dennis went from pro comps to AFRs so there has not been a direct comparison from vic jrs to pro comps....

.If you look around on various race forums there are lots of guys making big hp and running very fast with vic jrs.....I have yet to see that with pro comps...

Mavman went from Vic jrs to AFR 225s IIRC and saw no improvement!

I was simply comparing the ~50 horsepower Dennis said he picked up going from ProComp 210's to AFR 205's and the 50 or so horsepower Big Joe said he picked up going from Vic Jr.'s to AFR 205's.
In retrospect, I see that logic is flawed by the fact that we are dealing with two different engines. I guess that theoretically Big Joe could have picked up 80 or 100 horsepower on that engine if he had started with Pro Comps instead of Vic Jr.'s. And Dennis may have picked up 30 or 40 horses or more if he had switched to Vic Jr.'s instead of AFR 205's. I guess the one consistency in these two examples is that the AFR 205's made more horsepower than Pro Comp 210's or Vic Jr.'s on their respective engines. How's that for back-peddling???
Here again, I would still love to see a "head to head" comparison between the Pro Comp 210's and the Vic Jr.'s since that is the head they copied.

Well, year and half ago couldn´t have afforded anything better than PC heads, and they seem to have done their job ok. Now when I´m planning a new bottom end, replacing the stock, I wouldn´t waste money to build everything around my 185 PC heads. Wish I would have ordered the bigger ones, which seem to more better.

On the other hand, with something more expensive I wouldn´t propably started porting them, and learned how to...

This thread is starting to have quite much info on procomp heads, by the way.

JOE, appreciate your input, thanks for bothering to write here

I is sad that so many people still do not realize that in life, you get what you pay for, When something cost less, it is usually worth less. My advice to everyone is to always buy the best parts they can afford. This does not mean that your engine will be a world beater, but you wont have to go out andd by something over again.

JOE SHERMAN RACING ENGINES

So nobody thinks that the new adjustable long style clutch and sintered iron disc had anything to do with the increase in mph and decrease in ET? I'd bet it plays a bigger part than most realize. I doubt Dennis would run the same ET and mph with the old clutch. Just want to point out there is more to this than just a head swap.

I agree that there is a little gain at this time from the new clutch. I will say little because I have yet to be able to use the clutch as was intended in the first place. The static pressures that I need just to get clean runs down the track are 40-50% more than has been recommended by EVERY stick racer that I have come across. I have only scratched the surface of this clutch system for its intended purpose and it is being severely limited in its present state.

Here is something interesting related to my bore job, head swap, and freshened up motor. Last year, from the 1/8th mile to the traps, I averaged a 26mph gain, all in 4th gear (never had higher than a 26.2mph gain over that distance in over 80 runs).

This year I typically gain between 28.5-29 mph with every full run--that is with over 25 runs under my belt. Correct me if I am wrong (directed to anyone), but I believe that a 2 to 2 1/2mph gain can be pretty much all be attributed to a huge increase in HP since everything else, including tire diameter remained the same.

I've also seen a direct increase in performance on the street. Unlike last year, I can easily spin the tire in 3rd gear just by punching the throttle to the floor at any RPM above 3K--if I do it at a lesser RPM, the rear will break loose when it gets to 3K too. It is pretty scary to be be doing 55 mph in 3rd and give the car some throttle and the rear instantly wants to pass the front--sometimes to the left, but usually to the right!

I'm still thinking the hp is bringing you the extra mph and the clutch will give you the ET when you get it working properly.....Others have disagreed with me..

Originally Posted by frdnut

I'm still thinking the hp is bringing you the extra mph and the clutch will give you the ET when you get it working properly.....Others have disagreed with me..

How would your mph not go up if you were able to keep it accelerating better on the shift and launch? More average power throughout the run. Makes sense to me.

Dennis, you did say it shifted much smoother which is a sign that it isn't being pulled down so hard on the shift. Right?

Originally Posted by 289nate

Dennis, you did say it shifted much smoother which is a sign that it isn't being pulled down so hard on the shift. Right?

Good stimulating questions Nate--I am sure that I do not have all the educated answers but that is what discussion is all about.

Smoother shifting at high RPM is a well know benefit of a Long style PP vs. a diaphragm type (that I was using before.) I guess I should also mention that I chucked the old style gear lube for Mobil 1 synthetic which is also supposed to improve shifting. I am certainly not saying that the clutch did not give me some benefits, those are just not as apparent at this time.

Some additional thoughts to consider--60'er is now about the same as last year (1.66), and yet this year I needed 2" wider tires in order to achieve it. Also I needed to drop my launch RPM's much lower in order to cut down on the spin. Last year's end of year launch was typically at 4900. This year 4100 is still too high and the tires just want to spin off the line, even with low tire pressure and using last year's year end setup. That is not being caused by a clutch that is semi-slipping. I did make one change in suspension equipment, I swapped out the Summit/CE 90/10's for Calvert 90/10's.

As mentioned above, I am in 4th (highest) gear at least 100-150' before the 1/8 mile and am riding it out to the traps and getting better mph this year. MPH at the 1/8 is comparable to last year--less than 1 mph difference from the fastest 1/8's last year. Last year if I crossed the 1/8 at 90mph, I would get to the traps at at 114-115 mph. This year if I cross the traps at 90mph, I will hit the traps at 118. I still believe that this difference points to a good HP increase.

(Let's not get into the fact that my first 1/8 sucks.)

[quote=289nate;1411564]How would your mph not go up if you were able to keep it accelerating better on the shift and launch? More average power throughout the run. Makes sense to me.

[quote]


As Dennis has stated he hasn't seen much if any improvment in the first part of the run where he is launching and shifting..The big gains are in the second half when everything is locked up and he is WFO.....