[Ron H]

It's a performer RPM manifold. I think my numbers are good I just want to get that extra 1/2 second so I am running everyone down here in Sportsman. 12.50 to 16.00 is the class. The reason for the taller tire is traction. I was slipping the last few races. I finally tuned to where I am now. I started the season in the 14's. The track prep is inconsistent so with a real slick and it being a bit taller I should hook no problem.

[Geoff]

Ron H & others,
Sorry I got it wrong. When the chain stretches & retards the cam, the ICL will go from the original 104 ICL to a higher number. If it retarded, say, 2 degrees from chain stretch, the new ICL would be 106.

Ron H,
How do you like the 800 AVS?

[Ron H]

Yeah, that is how I remember it. Also though, If I want to move the power up the rpm hill I would continue to retard it, going higher in number or advance it, going lower in number? Maybe the chain never stretched and i am 104. Ultradyne said set it at 106.

[Lee]

What were your corrected HP and TQ readings? Even at altitude, those should "correct" to what I have at sea-level - shouldn't they?

I'll have to dig out my dyno charts, but I know my hp had not peaked at 4300! More like 4800. I still think you have valvespring issues, or else you'd have more power past 5000rpm.

BTW, my current converter flashes to about 3400, and I got 60' as good as 1.53 with 275/60-15 MT ET Street Radials and my UD 288/296.

[Ron H]

I don't know what factors to use to adjust HP for altitude. My car is a 68 firebird 3700# weight with me in it. My best 60' was 1.864. That was a 12.97 run 105 MPH. I think having a 3000 stall instead of my current 2400 it would help me. What tire pressure do you run? What suspension do you have? I am adding a set of slide a link's for next season which should improve things over the slapper bars I have now and adding some QA1 coil overs to the front. I have attached my dyno sheets.

[Lee]

Ron, rather crappy of them to just give you some generic numbers on that dyno sheet! The dyno's I've been on all explicitly state whether you are looking at corrected, uncorrect, or SAE numbers. Call the dyno operator, and ask them what they reported to you.

It needs to be updated, but most of the info at http://www.pontiacstreetperformance....uild45500.html is accurate still. I'm using 20psi in the ET Radials. I'm about 100lb lighter than you, and I AM at sea-level. Don't think that would account for 1.5 seconds and 8mph, but a set of bad valvesprings would :-)

Lee

[Ron H]

Corrected my times would be 12.25 @ 111 mph. That is .71 sec and 5 mph. That's not far off from your numbers.Maybe I just haven't tuned as well. Or the difference between our converters or a bit of both. I guess I won't take anything from the dyno sheets as some guys had suggested. They must be inaccurate. gregg merrick built my heads and i am sure he used good springs etc.

[screamingchief]

Ya'lls cars are "similar",but nowhere near enough to run exactly the same,at least from the information I have on this.

Some of the noticable differences,the tighter LSA on Lee's,torker II vs. RPM,the carbs ie. holley vs. AVS,1.65 rockers on Lee's,the convertors,gears,suspensions,weight,and so on.

And thats based only on what I know about the differences,sure there is plenty more of them,no two cars are identical.

More than enough to account for a .7 tenths difference,especially when the "altitude" factors comes in,as most of the factoring would still need to take into account any "atmospheric" factors as well,as its extremely rare to get perfect conditions at 4000 + ft. altitude.

So I feel things are'nt too far off here,Just really need to consider what you have and how it can be "refined" somewhat to meet your goal.

I think with your current setup,the move to a 3000 stall just wont make the difference your hoping it will make,you'll move thru the RPMs quicker,running out of steam quicker,passing up the RPMs where you making your torque currently quicker.

Now the taller tires may negate a small amount of that,and they will help traction,but I just dont think it will improve things much,at least not without further consideration.

Now you can play around with the cam timing and see how it reacts sure,but if you need to start retarding it very much to get it to run right,its very likely you needed a bigger cam to begin with,as most all the pontiacs I have had experience with usually all ran the best when the cams were installed advanced somewhat,regardless of their "size".

And yes,chain-slack does account for this to a degree as well, some of us know this, and take it into account as a matter of SOP...

And there are plenty of tuning options to explore as well,spacers,carbs,timing,shift points,traction,driving,and so on.

Good luck with this.

[Lee]

~8 years ago - same heads (with a bit less work), same cam/intake(Torker II)/carb (750dp)/transmission. Didn't have the rollbar, but ran steel wheels, so weight was about the same. Had 3.31 gears, stock torque converter, 1.52 roller tips - ran low-12's at 113.5mph.

~5 years ago - 3.42 gears, Hughes 2500, 1.65HS rockers, BFG DR's - ran a best of 11.77 @ 113.5mph

With the current converter, old cam, the MT DR's I ran 11.56 @ 114.5.

Swapped out the mechanical fan & pump for electrics, and ran 11.46 @ 115.6.

I'm just now starting to figuring out how to tune for the new UltraDyne/Bullet 280/280 solid lifter cam, but the bests to date are in the sig below. I'll be VERY surprised if I can't get it to run better than it does with the current tune.

I've played with 6 or 7 different converters since I've had the car. A converter has helped ONLY when I had enough traction. If you can't slam the throttle open to begin with, more converter will slow you down. My current converter wasn't worth anything with the BFG DR's, but kicks butt with the MT DR's.

Lot's of e.t. to be found with testing different jets with different timing settings.

Have fun!
Lee

[Lerry: The Body Ventura..]

Hey Cheif, you said most Pontiacs you've had experience with like cam advanced a little. I surely wouldn't think you would be running a cam advanced on a high reving, heavy breathing motor. A motor with good ported heads, a large lift and long duration cam, and a higher stall speed. These type setups make all their power in the top end area. Advancing cam wouldn't let motor get as high. I have mine installed strait up and sometimes wonder if I should have installed it retarded..

[screamingchief]

Hey Cheif, you said most Pontiacs you've had experience with like cam advanced a little. I surely wouldn't think you would be running a cam advanced on a high reving, heavy breathing motor. A motor with good ported heads, a large lift and long duration cam, and a higher stall speed. These type setups make all their power in the top end area. Advancing cam wouldn't let motor get as high. I have mine installed strait up and sometimes wonder if I should have installed it retarded..

I would just get a big enough cam to account for that situation and install it with some advance,thats all.

Besides,thats not the case in this situation,now is it?

Retarding a cam past split overlap (what most call "straight up") indicates to me that the cam is too small for the intended application.

Conversly needing to excessively advance a cam to get it to run right would indicate the cam was too large for the application.

Most all cams will have some advance ground into them,and this is for more than one reason.

A larger cam installed with some advance (say 4*) should have the intake valve closing at roughly to the same time as the smaller cam when it is installed in the split overlap ("straight up") position,and generally speaking the larger cam/advanced combo will run better.

I would much rather be a little "overcammed" and need to advance the combo,as opposed to being "undercammed" and needing to retard the combo.

And the LSA has a lot of influence here too,tighter LSA's narrow the power band down somewhat,and this makes these changes more noticable as compared to a combo using a wide LSA cam.

Each case is unique,there is no real one size fits all rule to use for ALL cases,it just my opinion here that Ron MAYBE slightly undercammed,but he CAN determine IF this is true by trying things like retarding the cam some,or trying 1.65 rockers (if it were a solid cam,he could try varying the lash too).

He might find that it in fact is cammed just right with those subtle changes like that,but if it needs to be retarded much past say a 106-108 ICL,it starts to look more and more like its just slightly undercammed to me,thats all.

JMO folks,FWIW...

[Ron H]

Screamingchief. Would it not make a difference if it was 104 instead of 106 where Ultradyne says to put it at? That is what i am thinking. Also I found a set up I am interested in and want some opinions. Hyd roller comp cams part # 51-813-9.It has 252/262 @ .050 106 lobe separation .375 .366 lobe lift. that would be .552 .549 with 1.5 rockers. Would this cam work well in my engine without changing anything else? I know i would need to change springs in my heads. Or would leaving the cam and everything alone but getting a race port on my heads benefit the same or better? Or would i need to port to get the advantages of having this cam in my combo?

[screamingchief]

I absolutely recommend trying to retard the ICL some and see how it reacts,if it does pick up some it will give you an indication of the direction you need to look for further gains,and if you reach a point where your satisfied with the performance,it has'nt cost you an arm and a leg to achieve that.

Next thing I'd recommend is trying a set of 1.65 rockers on it,again if it picks up it also indicates the direction to follow.

Of course the 1.65 rockers would require the pushrod slots be opened up for clearance,but that is'nt all that major of a deal either.

Now for that cam,that is a BIG hydraulic roller,WAY too much IMO,this one would require much more than just "ported heads" to get it to work it's best.

I dont think your needing major changes,more like minor,a good hydraulic roller for these type of 455's is the comp xe288hr,this cam with say a 3000-3200 convertor and your gears it will be a monster,easily a "solid" 11 sec car @ sea level.

I myself would likely just use a solid cam like I mentioned earlier,which is close to what Lee has in his now,its more of a refinement of the UD hydraulic grind,just slightly bigger,with the benefits a solid cam has to offer.

As long as you dont go crazy with the lift major head work should'nt be needed,and of course porting will always offer substantial gains across the RPM range so it is ALWAYS worth considering in the quest for performance regardless of the cam being used.

[Lerry: The Body Ventura..]

Chief, I wasn't meaning Ron's problem. I meant what you said in general. I thought you meant all cams you use is advanced. When one changes heads, intake, rockers, etc. Without having to tear engine down and replace the cam everytime one upgrades. He can retard the cam when upgrading if needed.

[Ron H]

I think I will check the position of the cam. I am going to change the damper and water pump so it isn't much more to pull off the timing cover and check the degree. The best move then without dishing out alot of money is porting the heads more. I am going to a 3000-32000 stall converter. Also a Ruggles quadrajet. Slide a links instead of slappers and QA 1 coil overs in the front. Real slicks. I think i will see benefit from that without having to tear in and build the engine again. Though after the porting is done on my heads i will have spent as much on them as i would have a set of KRE D ports. But I wouldn't have been able to race this season as they were way behind on production of them. My brother told me to go to a solid cam to begin with but i didn't want to deal with lash. These boards are great. If someone really does some reading and pays attention they can save some money and build a really great machine. Thanks again for all the help.

[screamingchief]

Lerry,pretty much every cam I have used in pontiacs has been at/or advanced from "split overlap/straight up" (often beyond what has been ground into the cam already),if I had one that needed to be retarded from S.O./S.U.,I would likely replace it with a bigger one and install it at/or advanced from "S.O./S.U.".

And most all the folks I know who run the "bigger" stuff do the same as well.

I dont mind changing cams if need be,the real "trick" here is to know what you need before you put it in the car.

And if your "upgrading" other items,often a cam change is just another part of that puzzle.

Everybody has they're own approach to these things this is just one of my ways to manage this,not all that big a deal though.

I myself will only advance or retard a cam so far before it becomes obvious to me another cam is in order.

JMO/FWIW...

Ron,sounds like a plan,if you do consider a solid I would'nt be too concerned about the lash issue,the better modern tight lash grinds with good valvetrain pieces rarely need attention beyond checking it once or twice a season,and maybe restting it once a year for the sake of being thourough,no big deal really,it also gives you another tuning option to have at your disposal.