[GTOINDY]

Originally Posted by screamingchief

Was the cam degreed?
Or just "line up the dots" and assumed to be "straight up"???

I'd at least try advancing the ICL to 104-102 degrees or so first...

It was degreed in at 4 degrees advanced so 104 but it was my first attempt at degreeing a cam so in an attempt to figure out the problem I reset it by "line up the dots" method with no change in performance.

[screamingchief]

no change in performance.

If things like advancing the ICL and loosening up the lash (simulating a "smaller" cam) are'nt having any effect on your cars performance,I would feel the problem is not with the cam likely.

JMO.

What has changed since the 12.53 runs???

How were the traction issues you said you were having overcome?

[GTOINDY]

Originally Posted by screamingchief

In that other thread you said you had gotten some mid twelves (12.53 IIRC) out of it but were having traction issues,what's changed since then???

you are correct the first day to the track it ran a 12.53 on small street tires 26" tall. I have also switched to the RPM intake hoping to get some low end torque

[se428bandit]

Have you checked to see if your getting full thottle.

[screamingchief]

Sounds to me like it wants more gear,and the single plane intake to work well with the rest of the goods you got.

And possibly more convertor,but I'd hold off on that for now.

The smaller tire upped the effective gear ratio,in all gears.

This in turn effects how the convertor is going to act as well.

And some combos that dont spend as much time in the lower rpm range may not see much benefit with the RPM like it may with a single plane.

I cant say I'm suprised the changes made had a negative affect on that combo,quite the opposite,the 400 is often going to use a bit more RPM to get the power needed to run good numbers,it's not a 455 after all now is it,why try to make it one...

The factory 400 HI-PO cars all came with at least 3.90 gears,the really nasty ones had 4.30's in them!

My advice would be to try the ICL advanced to the 101-102 neighborhood,and try the combo with the tommahawk intake on it with a 1" spacer (seeing as how it closely rivals the RPM in many respects),and consider some more gear out back or a low gearset for the trans to get the car moving out of the hole better with the "bigger" tires,then see how the convertor is getting along with things at that point.

And further head porting would have a big effect naturally as well.

[GTOINDY]

I am leaning towards a cam change rather than changing everything in the drive line and reworking the heads. I would like to get this car moving a little better before Norwalk. What cam should I use everyone seems to really like the XE274 but I have allready made one or two mistakes just looking for some input.

[GTOINDY]

Originally Posted by se428bandit

Have you checked to see if your getting full thottle.

Yes bandit I have checked and it is getting full thottle I have owned a lot of Pontiac's all in stock trim and never had one run this badly.

Vince

[GTOINDY]

any cam advice? I am about ready to put it on the street with a ram air 4 cam and say the hell with it.

[screamingchief]

There is no guarantee that it will pick up anything by just changing cams either.

Might even end up being slower yet..

You never know for sure.

But consider this,most "stock" 400's with the RA IV cam at best get dyno numbers close to those you quoted for your combo (450 hp @ 5500) as you stated it dynoed at,the RA IV they tested in ME (sept.05) made it's best pull at 445.9 HP @ 5900 RPM,and that was with the "better" RA IV heads,though stock HO/RA manifolds (intake/exhaust).

So when you take into account the oft qoted +10 degrees or so (methinks a bit more than 10 degrees in most pontiacs) for a solid to hydraulic cam comparisson,your cam aint a ton bigger than the RAIV hydraulic your considering as a replacement in my thinking.

And the dyno numbers would suggest the same as well.

Your cams tighter LSA would likely be "peakier" in the mid range numbers than the wider LSA RA IV stick would be if I had to guess.

What you would be trying to do by going to the RA IV style cam would be improving the area "under the curve",and not knowing how your dyno test was beyond the peak numbers makes it hard (for me) to draw any conclusions there.

The LSA would be the biggest difference likely.

So If I were going to make a recommendation,I myself would say stick with a solid cam,go just a tic smaller on .050" duration (low-mid 240's intake,high 240's to low 250's exhaust),and probably get it on a 112 LSA,kinda like the crower solids are (#60310 0r #60311) or on a 110 LSA like the lunati (#407A1-LUN or 407A2-LUN) solids are.

Another good cam to consider would be a custom ultradyne/bullet solids.

Hopefully that should pick up the numbers under the curve,without killing your current peak numbers any.

And as far as the heads go,the extra flow should'nt hurt the perfomance in any way,so if you can afford it,there is no reason to ignore it.

but I have allready made one or two mistakes just looking for some input.

Sometimes you gotta stick with your gut,and work thru the issues and not be tempeted to "cut and run" from the mistakes by making knee-jerk decisions/changes,and instead stay on the path you started on,and work your way thru the issues untill the path beyond shows itself.

You try things,if they work,you keep 'em,if not,go back to how they were before,and try to improve things from there.

Cheap easy stuff first!

Advance the cam more,put the single plane back on it,and run a shorter slick and see if you can get that to hook,and see how that does.

My car has 28.5x10.5-15's and 4.10's that I'm going to be running with my very similar 400,so yeah I feel that's likely what it'll take to get the performance your looking for here,JMO/FWIW.

I think yours as it was/is (single plane,advanced ICL and such) with just adding some 4.10's and the same 28.5x10.5 slicks I run and maybe a little loser stall (3200-3500) would easily be in the low 12's to high 11's.

But if you choose to go the other route,that's cool,let us know,and good luck with it.

[GTOINDY]

Thanks for the suggestions. I am heading to the GTOAA nationals this week and I am just a little disappointed in this car. I busted my a$$ all winter and just not happy with the performance at all. I took my 70' for a ride the other day and boy it is so much more fun to drive. The 70' is slower my best time was at Norwalk last year it ran a 13.67 @103mph during a time run but it does have a 455 in it. I am just very discouraged after working so hard to get it done.

[screamingchief]

I know what your talking about,but this is the hardest thing to have to deal with on new builds often,and it takes the greatest amount of restraint to deal with IMO.

The temptation to dump a specific item in the combo and lay the blame for the poor results is very easy to do,too easy IMO,any changes should only be made after plenty of testing has determined it is justified,and this way you should hopefully come to a sound conclusion where the root of the problem lies,and how best to address it.

You went to the trouble to dyno this engine,this gave you a known baseline to work from,if a change has a negative impact,it's best to return to your known baseline and try again from there,bank any gains,cut any losses.

Make single changes at a time,it's virtually impossible to quantify changes when more than one change is made,as there is no way to determine what effect any of the changes made +/-/= .

It takes a methodical process of trial and error to distill a combo down to the finest state of tune and performance,and some people have taken years to get their combos worked out to that level,others just find a combo that works thru "dumb luck",or by duplicating another "known" combo,but even trying that can backfire easily enough.

Hardest thing to have in racing is often patience...

[GTOINDY]

well a friend had a 4500 stall torque converter sitting on his shelf and loaned it to me (great guy thanks Roy). The car felt a lot better it went a 12.41@105mph with a 1.68 60'time which was alot more fun to drive. Now I need practice I am just not very good at the tree.

[screamingchief]

Glad to here it's heading in the right direct again!

I do feel the combo should be able to do well,just gotta work with it and see what it likes.

Seems to like the added stall enough,and I still feel it will like a bit more gear and/or bit shorter tire too.

May not be as "Street" friendly that way though,but no pain no gain,right???

Any other changes?

Was this with the RPM/carter carb you had on it last?

And which tires?

I think for a deal like this,the tomahawk or torker II would be best intake,port matched to the heads,with a nicely worked holley 750-800 DP,and at least a 1" spacer (I would try 1" open & 4 hole,and if room permited,try both in 2" too).

Get it into the very low 12's to high 11's on the motor,then spray the snot out of it to get the most out of it possible,maybe even into the 10's,that's the plan for mine.

[GTOINDY]

Originally Posted by screamingchief

Glad to here it's heading in the right direct again!

I do feel the combo should be able to do well,just gotta work with it and see what it likes.

Seems to like the added stall enough,and I still feel it will like a bit more gear and/or bit shorter tire too.

May not be as "Street" friendly that way though,but no pain no gain,right???

Any other changes?

Was this with the RPM/carter carb you had on it last?

And which tires?

I think for a deal like this,the tomahawk or torker II would be best intake,port matched to the heads,with a nicely worked holley 750-800 DP,and at least a 1" spacer (I would try 1" open & 4 hole,and if room permited,try both in 2" too).

Get it into the very low 12's to high 11's on the motor,then spray the snot out of it to get the most out of it possible,maybe even into the 10's,that's the plan for mine.

I do agree the shorter tire or gear would help. My rpm it was around 5400 in the traps so there is a little left. I did not change anything else so I may go back to the Torker I as a test because that’s what it was dyno'ed with. I have no plans to spray this motor. I plan on working on the suspension and the driver mostly.

Vince

[screamingchief]

Sounds like a plan,I'd also recommend after swapping and seeing what difference the intake makes,that you go ahead and try redegreeing the cam advanced like it was before at 104,or maybe even at 102 ICL,with that cam & engine combo you should still have plenty top gear pull with it advanced,and this should help the midrange power/torque some and it should still pull good to like 6200 or so RPM easily,so yeah more effective gear ratio will help more than likely,the RPM is there for sure if your going thru at 5400.

I understand 'bout the spray,was just thinkin out loud 'bout my project,I plan on hammering mine hard,so I been slowly collecting bits and pieces for the next couple of engines that will likely end up being needed if I go too far.

Good luck and keep us posted!

Bret.

[Cliff R]

I went to the track with Vince and even swapped my carb from my car onto his engine, ran almost exacty the same. I drove his car down the track, and it just doesn't "pull" like it should. There is a pretty good "rush" of power up near 4500rpm's, but it is lacking some below that, and even above 4500 it isn't as strong as it should be?

My guess is that the static compression ratio is quite a bit lower than it needs to be for that big of a camshaft. We've cc'd #13 heads that were up near 78cc. If the pistons are .020-.030" in the holes, combined with 75cc or so heads, the static compression ratio is pretty "low".

We tried timing and fuel, and the engine didn't respond to either one. Could have been partly due to the high octane fuel, it sure wasn't helping much? I know a few folks running very similiar combinations of parts, and running into the 11's, but they are using cams in the 230-240 range. This would probably be the best place to start, FWIW......Cliff

[Ron H]

The cam is a bit big for your combo but not unusable. It is close to my cam in the 462. It is a bit larger than a 041 HYD but with a better ramp because it is a solid. Part of a problem is the tight LC so the power band is tighter. You should do as Bret suggests and advance the cam to 102*. That will push the power into a lower RPM range so it will match your combo better. The low CR and lack of porting is really what is holding you back right now. I would leave everything else at this point and work the heads. So you have a choice, get a cam that matches the combo better or re degree the cam and work the heads IMO. www.bulletcams.com will grind you exactly what you need for the combo you have now. You are making good times. And you are heading in the right direction at least with your steps so far.

[scott70]

I used to run the ultradyne 231-239 @.050 hydraulic with rhoads lifters and ran 11's with that,that was a great cam.A friend of mine runs a 400 gto and going from 4.10 gears to 3.73 gears slowed him down on the track.If your going to run a big cam in a 400,you need gears and a converter,especially in a heavy car.

[screamingchief]

I would tend to agree the compression could likely use some attention here,sure,at the minimum I'd say use the .027"/4.160" cometics to help that a little,at best zero deck the thing,and maybe mill the heads a tad,and use the .040"/4.160" cometics.

For those who may wonder what my interest in Vince's combo is,I have had a very similar combo to Vinces in the works for a while now,and I feel this one has a close relation to what I can expect from mine,my combo is more a matter of default though,as lots of it was accquired "as is" and the situation has often dictated that things be used as they are.

It's true the 13's do tend to be the high end of the early big valve heads chamber-wise,most use this fact to try and "squeek" by when using pump gas with the "hi-comp" heads,for my deal like this I have 670's,which are usually towards the smaller side of chambers for these heads,as these use the closed chambers.

FWIW my TRW's (L2262) measured .020" in the hole,just like the catalog states they are.

My motor was aquired Fresh/assembled,so this was'nt necessarily my choice,but I'll work with what I got till opportunity affords me the chance to correct these things.

This is why I plan to go with the thin cometics the next time I pull the heads on mine,to bring the piston/head clearance back to the .040"-.050" range where there is some degree of "squish",albeit down in the hole a bit,so it's a compromise,will have to do for now,as I cant pull it all apart just to zero deck it,if it ever needs to come apart for another reason,then it will likely be done at that time.

I feel lots of folks are looking at this and are just reacting to this cams percieved "size" and the fact it's in a 400 and dismissing it as too "big",and then go on to recommend a hydraulic cam in the 230-240 neighborhood,well IMO this SOLID cam is'nt a whole lot "bigger" than said hydraulic cams are,and from the info that was given on the dyno results,it seems to agree with this fact,though it would help a bunch to see the full dyno results to know more.

I've always felt the "HYD/dur.+10 degrees = SOLID/dur." was/is off for most pontiacs,I've always felt it was more like +15 or so degrees,that's why I feel many fall short on cam when changing from their hydraulics to a solid in pontiacs.

Remember,Vince's engine reportedly dyno'ed at 450hp (@ 5500),from a more or less "stock" 400,with little more than a "clean-up" on the heads,said "big" cam,and "bolt-ons"...

Not bad IMO.

Consider that some folks with a whole lot more time and effort into their combos are often only up 50 or so HP on that with more sophisticated assembly and hardware like heads with better flow #'s (often aluminum),in some cases hydraulic rollers,and/or cubic inches to boot!

400's are a somewhat different beast from the 455's.

The difference is often the fact that the 455 brings a healthy dose of torque across the board to it's "A" game as a side benefit,which is not always the case with the 400.

So the driveline needs to be set-up to address this fact.

One has to work with what they have often.

Consider how a stock or super stock "class" (NHRA/IHRA) 400 ci. car has to get to their levels of performance.

WAAAYYY more work I assure you,not to mention lots "O" gear and convertor!

Thing is I am fairly certain this basic combo with minor changes can get into the 11's with the right running gear,if the effort is made.

Or you can chase the combo further by trying things like the cam...

His choice,no sweat off my back,I'm just trying to help with things as they are now.

But I doubt he'll find what he's looking for there either,and then ya' better be prepared to change things further yet again,JMO/FWIW.

I'd say work with the combo a bit more,knowing full well there is an easy 40-50 or so HP likely to be gained by further head porting (250-260 cfm) and refinements to the engine (zero deck,compression,etc.),and possibly a bit more with further tuning/testing,beyond that you might as well consider upgrading the whole deal with more cubes and further flow improvements (300+).

Lets face it,600 hp 400's are few and far between,that's why god gave us 400 ci. racers nitrous!

I know,I know,Vince is'nt gonna spray his...

But I sure am!!!

[Junkyard Dog]

Well, you have the convertor, now get the gears. With a 29.5 inch tall tire, and that is TALL, use a 4.30 - 4.88.

Then port the heads to match the rpm range you have chosen for yourself. Think about it this way. You are now running a 4,500 rpm stall speed. If you took your heads to a porter and said that you were running a race car that will never see below 4,500 rpm, would they suggest a pocket port or mild cleanup?