[lust4speed]

Lets get away from downshifts. How does it perform when pulling all the way through the gears from low RPM to where it shifts up. Flat spot, bog, or other drop off in performance up through the gears? How restrictive is your exhaust from the head pipes on back?

Even dumping plumes of black smoke, the combination should still motivate very nicely.

[Cliff R]

The static compression ratio has a MAJOR impact on power (torque) production with that cam in the 400 engine.

Cam placement is equally as important.

I've had several folks email me with similiar results as you are having. In every case the cam was not advanced enough, ICL up at 112-113 degrees, which is usually where those cams end up at "dot to dot".

I wouldn't use that cam at 9 to 1 compression in a 400 engine, a smaller 068 size cam would be a better overall choice, as it would produce considerably more low end power much earlier in the rpm range.

I can tell you this for certain, with early unported big valve heads, 10 to 1 compression, and that cam, it should just about tear your head off from about 2800-5500rpm's. If it doesn't, something is amiss in the basic "recipe", or tuning is WAY off the mark, on combinations of both.

Right on the dyno with a very basic 400 engine, flat top pistons, unported #16 heads, etc, that cam made 419hp/453 torque.

With KRE heads and a tad more compression 440hp.

The larger 60243 cam made 424hp/465tq, and 450hp with KRE heads.

The even bigger 60919 (RAIV clone) made another 10hp (KRE heads), but idle quality was crap, and the engine was "sluggish" below 3500rpm's. Most likely why Pontiac reserved the RAIV cam for the round port engines, with 3.90 and taller gearing.....IMHO......Cliff

[Skip Fix]

"Right on the dyno with a very basic 400 engine, flat top pistons, unported #16 heads, etc, that cam made 419hp/453 torque."

And what mph and vehicle weight did it run? Superflow formulas just don't show that based on airflow without alot of optimization and they are pretty darned close when you use them,and neither do my dyno results on a conservative dyno(ie engine dyno showed same HP track mph/wt did). Moroso slide shows 419 pushing a 3800 lber to 11.60s @113! Assume a street/strip suspension I'd go less on the ET(low 12s high 11s) but mph is pretty darned close to right on. I just can't see a basic 400 unported D ports running even low 12s @ 108,which is around 365 hp.

The 400ci NHRA stockers running those times(deep 11s or high 10s) with "unported iron heads" have a HUGE cam,loose convertor,lots of gear,open headers and about 20 years of tuning that particular car.

"With KRE heads and a tad more compression 440hp."

I would sure expect the better flowing KRE heads to be worth more than 21 HP over non ported iron D ports, 260 cfm vs 215-220? And then the bigger cam lost 16 hp but picked up 13 ft lbs?

[Cliff R]

"I just can't see a basic 400 unported D ports running even low 12s @ 108,which is around 365 hp."

Skip, just helped a customer with a similiar engine set up his 68 FB, using the larger 60243 cam, first outing netted mid 12's at over 110mph spinning some on the starting line.

Another customer and good friend of mine has a milder deal with 62's and the 60916 cam, full weight street driven 67 GTO, 3.23 gears and TH400. He runs 13.0's at 108-109mph in hot/humid weather. Don't think he's raced it other than a few passes at Norwalk in August temps. Should be good for solid 12 second runs in good air, and certainly quicker if he put some gear in it, as 3.23's just aren't optimal for that much weight and a pretty "mild" 400 engine.....IMHO.....Cliff

[Skip Fix]

110 in a 3800lber 387 hp and right where my RAIV 400 ran at 3900lbs and 385 dynoed HP. 108 drops us down to 367 hp. Both short of the 419 number.

Heck Norwalk August temps are our late fall temps here Cold front today supposed to actually drop it below 90!

[Cliff R]

I don't know Skip, maybe in the "perfect World" where there is never a head wind, or a brake dragging, etc.

Keep in mind that neither example I gave is any sort of a "race" car, and not optimized for gearing/converter either.

I'd say mid-12's from a "daily driver" Pontiac at 3700-3800lbs in full street trim with a pretty "mild" 400 engine is flat get-er-done, in any weather.......Cliff

[gtofreek]

I would not have built that engine with a dish piston unless I was building it with a VERY mild cam[204° @ .050" or less]. My guess is the Icon 10 cc dish piston. That's just not enough compression. You should have flat tops and be closer to 10:1 to make that work right. With a tight quench[.040"] and the cam degreed properly, it should run fine on premium pump gas. I would ask the engine builder where he degreed it to. It needs to be installed between 106° to 108°. I would shoot for closer to 106°. If it is straight up, it won't run good no matter what you do. Too many guys install cams straight up. I NEVER install a cam straight up. That's the best way to make a dog out of your combo. Some cams however, are ground with advance into them, and may need to be installed straight up[dot to dot], but they need to be degreed to verify. If a cam is ground on a 112° lobe separation, then, if it is installed with no advance, the intake center line will be 112°. Way too retarded. That cam needs 4-6° advance put into it. The cranking compression test should tell you something.

I installed a roller cam once and installed it straight up so I could get a starting point when I degreed it. As it turned out, installed straight up, the ICL was 96° The cam was ground on a 110° lobe sep. Now, wrap your head around this, I had to retard it 10° to make it 4° advanced! I wanted it at 106°. If that was installed straight up and not degreed, that engine would have bent a bunch of valves on crank over. One can never assume things are done right, especially with camshafts.

[Verdoro 68]

Did a compression test this morning. I took a drive around town before I did the test and removed all the plugs. The good news is that every cylinder is in the same ballpark. The bad news is the compression seems really low.

1 - 145psi
3 - 145psi
5 - 145psi
7 - 145psi

2 - 145psi
4 - 145psi
6 - 150psi
8 - 140psi

Does this say anything about how my cam is installed? I could take the front cover off and take a look at the timing set. It's a 9-way set so it should tell me if he advanced it or not.

Plugs 2 and 4 were fouled. Not sure if they just aren't getting good spark or what.

[lust4speed]

I believe a leak down test would tell you more about why plugs two and four are oil fouled. Pressure readings at cranking could be an inaccurate gauge, bad hose on the tester, or slow cranking. Or they could actually be a little low.

My definition of straight-up is installing the cam according to the cam card. It might not be dot-to-dot because of manufacturing tolerances or machining errors with the cam, crank key slot, or timing gear set. So if the card says install at 106°, then that's the straight up position. IMO Installing that cam 4° advanced would be putting it at 102°. Because of the ambiguity of the term, I usually just avoid using it and refer to what the cam card calls for.

[400 Lemans]

I agree about the cam timing. Tear it down and put the 4 to 6 advance in it and you will be flying in no time. Crowers are nice cams but almost everyone here who runs them has to go through this same thing. Do a search here on it. The rest of the combo sounds good.

[grandville455]

Those crower cams are known to be off, u really need to find out what the builder did, or just degree it yourself then u will know, but if it was set straight up, dot to dot. I can almost bet its way retarded with that cam. I would also do a leak down, especially on those two that are fouled.

[68 Firebird]

Out of curiosity has anyone ever degreed the melling spc-7. I set it up dot to dot
and used the napa wide link timing set. Never did degree it and always wondered.

Maybe that will be my winter project. Problem is it's running very well and hate
opening a can of worms.

Verdoro I can blame you for wanting more we are all guilty of it!!!!!!!!!!!!!!!

Gerry

[Ben M.]

Originally Posted by 68 Firebird

Out of curiosity has anyone ever degreed the melling spc-7. I set it up dot to dot
and used the napa wide link timing set. Never did degree it and always wondered.

I've never had to. Put the cam dot to dot with the timing set and the engine runs beautifully and powerfully all the way up to 95-100MPH. Never taken it to the track or anything like that though.

[scott70]

Originally Posted by grandville455

Those crower cams are known to be off, u really need to find out what the builder did, or just degree it yourself then u will know, but if it was set straight up, dot to dot. I can almost bet its way retarded with that cam. I would also do a leak down, especially on those two that are fouled.

You got that right.My engine shop was trying to degree in the crower 60919 cam they got and things werent coming out right. They told me they checked it and it looked like the cam was ground at 123 degree LS! So they called crower and said what they found and ordered another from them (which they had to grind one cause they didnt have one there) The next one they got checked out at 115 LS instead of the 113 its supposed to be. They used it and degreed in at 108 ICL instead of 109.Close enough I guess.

[gtofreek]

Was the pic of the oily intake runner cyl. # 4? If so, find out where that oil is coming from and that might fix the fouled plugs. #2 and 4 intake runners are right next to each other so maybe your getting a little leakage past the gasket between #2 and #4 runners.

[Verdoro 68]

Any possibility the oily 2/4 plugs are due to the PCV valve sucking too much oil?

Since the consensus seems to be that my cam needs to be advanced - is there a way to degree it without removing the cylinder head? Can I pop the timing cover off and move the sprocket ahead 2 or 4 degrees and be done?

This might be a dumb question, but will advancing the cam increase the cylinder pressure? 140-150 seems really low to me.

[Mister Pontiac]

Originally Posted by Verdoro 68

Since the consensus seems to be that my cam needs to be advanced - is there a way to degree it without removing the cylinder head? Can I pop the timing cover off and move the sprocket ahead 2 or 4 degrees and be done?

This might be a dumb question, but will advancing the cam increase the cylinder pressure? 140-150 seems really low to me.

Yes. You can remove the timing cover, pull the chain, install an 'offset key,' OR with the 'multiple keyway' gear, you can move that then put it all back together. That's the simple fix, but you still won't know what you have until you degree it.

And yes, you certainly can degree a cam without removing the cylinder head. To be accurate though, you will want to pull the valley cover, install a 'solid' lifter, then put the dial indicator on top of it. Or, you can pull a rocker arm, then put the indicator on top of the pushrod where it protrudes from the cylinder head. Either is fine.

I will say that there is probably no simpler fix to a 'doggy' street engine than by simply advancing the cam, regardless of where it's at now. And with your 140-150 lbs of dynamic compression, I agree you're a little bit low. I think the 160 range would be better, and the quickest way there is by advancing the cam 4 degrees.

Years ago, I did this very thing on an old 400. I had no idea what I had, but I knew it was a lo-po version, and it was just sluggish across the board. I did nothing else except install a 4 degree offset key in the cam, and put it all back together. The first test drive proved the point. After a couple hours of work, the 400 came alive, and the 'seat of the pants' feel was instantly recognizable! And when you're in your early 20's on a budget, I took anything (free) I could get! Of course in those days, I was very "tool poor" and very rudimentary in knowledge, so I have no idea how much I really changed things in actuality. I'm sure there was still more to be found, but it was still a great learning lesson.

Good luck, and keep us posted!

[gtofreek]

Yes, advancing the cam closes the intake valve sooner, thus increasing cylinder pressure which is what makes torque. It also opens the intake valve sooner so when the piston starts back down the hole, the valve is open farther, thus breathing better as soon as the piston starts sucking. You get more in the cylinder and trap more there. That equals power. That is why retarding the cam just doesn't work.

[gtofreek]

I would not recommend just changing to the 2 or 4° advance keyway without knowing where it is now. I'd call whoever built it and ask them if they know where it is.

[Verdoro 68]

Makes sense. I'll give him a call Monday morning and see if he can remember how he set it up. Based on the way the car runs, I bet he installed it straight up. There's a power curve, but it feels lacking across the board.

I appreciate the advice. The amount of knowledge on here never ceases to amaze me.