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Are the heads ported and what rpm do you trap at now..
and are you happy with the rpm... do you want to go up
in rpm..which you will unless you change gear ratio

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yes they have been 346 on intake and 236 on exhaust or somewhere around there sheets in the basement...shift at 6500 rpm going thru traps about 6700 rpm

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Are the heads ported and what rpm do you trap at now..
and are you happy with the rpm... do you want to go up
in rpm..which you will unless you change gear ratio

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yes they have been 346 on intake and 236 on exhaust or somewhere around there sheets in the basement...shift at 6500 rpm going thru traps about 6700 rpm

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At what lift was the max flow... you want to exceed
that lift to utilize the max out of the head

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Are the heads ported and what rpm do you trap at now..
and are you happy with the rpm... do you want to go up
in rpm..which you will unless you change gear ratio

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yes they have been 346 on intake and 236 on exhaust or somewhere around there sheets in the basement...shift at 6500 rpm going thru traps about 6700 rpm

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At what lift was the max flow... you want to exceed
that lift to utilize the max out of the head

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700 lift they were ported by Nick @ compu flo. my thinking is the current cams duration is a little high for my comp ratio even though it seems to be working good just trying to tweak it as much as possible....time in my sig is with good air

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I run a 'small roller' 620 lift, 272/276 @.050 been 10.20's 130mph with the crossram thru the exhaust. Put your intake and dominator on my motor probably easy 9's and car weighs 3300lbs. 4.30 gear 29.5 tires, little ez heads. The cam is from Indy R1, it's easy on the valve train.

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Jim I was told to leave it alone another cam won't help me but chasing that 9 sec time slip it hard for me not to touch it.

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What's it 60 ft?

Why do you think you should change the cam?

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What's it 60 ft?

Why do you think you should change the cam?

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I was going to ask the same question. If you raise the stall, It might wake it up or just be in the range the cam you have will work best. What is the LSA of the cam? Where do you have it installed? What are you shifting at now? 1.7 rockers on the intake may work well, but I have no experience with a setup like yours. I am assuming these are big port heads?

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Just thinking duration is to high for my compression and to much overlap. Lsa is 106 now, tried different shift points made no difference. heads are indy ez-1 MW ports

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What's it 60 ft?

Why do you think you should change the cam?

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I was going to ask the same question. If you raise the stall, It might wake it up or just be in the range the cam you have will work best. What is the LSA of the cam? Where do you have it installed? What are you shifting at now? 1.7 rockers on the intake may work well, but I have no experience with a setup like yours. I am assuming these are big port heads?

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Just thinking duration is to high for my compression and to much overlap. Lsa is 106 now, tried different shift points made no difference. heads are indy ez-1 MW ports

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You need more lift to utilize you flow.. but I would
talk to a few cam companies.. one of them would be
Bullit Cams.. they make some nice ones but they do
tend to be aggressive

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What's it 60 ft?

Why do you think you should change the cam?

Also, your #s just look odd to me... almost 4 mph faster in the 1/8th than me, yet only 2 mph faster in the 1/4, like you're running out of rpm or over geared.

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Or, maybe it's the valvetrain. Was the valvetrain checked for proper geometry? A stock stroke 440 with 346 cfm heads and 282 @ .050 cam should be shifting higher than 6500 rpm. I think with a 31 x 14 slick and those engine specs, it would need more gear. I'd expect peak power to be more than 6500 rpm. It just needs to get there. That would explain the lower 1/4 mile mph.
That being said, it could benefit from more lift, and if the cam is being changed anyway, I'd go with a little less duration, and a higher ratio rocker.

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Those heads on a 451 will run best at a higher rpm by a bunch. You might be losing a lot to bad valve springs and lousy valve control. A motor like yours shouldn't quit making power till well into the 7,000 rpm range. If you have very good rockers and pushrods, put some good springs on it and get a cam that has somewhere around 276 to 280 duration, 108 or slightly higher LSA, and .700+ lift. Isky has a RR735 grind that looks good on paper for your application. It has 280/288/110 duration numbers, .735/.684 lift numbers.
I have run this cam in my 528 and it pulled power past 7200 with a single four. If you cut your heads for some serious compression, (13+) this cam ought to make serious power. Put a 6,000 plus stall converter in front of it, and hang on.

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I think we are on the same page here Greg. Big cam with small cubes is going to need more rpm. I think it has valvetrain instability, which will weaken the springs prematurely. Could be a combination of both at this point. I do think a smaller duration cam would help the bottom end some and avoid more gear and maybe get away with his current converter to get that 9 sec slip. It all comes back to whether or not he can turn the needed rpm without the motor laying down.

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I run a 'small roller' 620 lift, 272/276 @.050 been 10.20's 130mph with the crossram thru the exhaust. Put your intake and dominator on my motor probably easy 9's and car weighs 3300lbs. 4.30 gear 29.5 tires, little ez heads. The cam is from Indy R1, it's easy on the valve train.

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Jim I was told to leave it alone another cam won't help me but chasing that 9 sec time slip it hard for me not to touch it.

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You know my thoughts on this.............. I can get ya .2 more than likely according to how screwed up your carb is. My cam is 276-281 and has no issues idling or goin past 7000 BUT more cubes.

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Those heads on a 451 will run best at a higher rpm by a bunch. You might be losing a lot to bad valve springs and lousy valve control. A motor like yours shouldn't quit making power till well into the 7,000 rpm range. If you have very good rockers and pushrods, put some good springs on it and get a cam that has somewhere around 276 to 280 duration, 108 or slightly higher LSA, and .700+ lift. Isky has a RR735 grind that looks good on paper for your application. It has 280/288/110 duration numbers, .735/.684 lift numbers.
I have run this cam in my 528 and it pulled power past 7200 with a single four. If you cut your heads for some serious compression, (13+) this cam ought to make serious power. Put a 6,000 plus stall converter in front of it, and hang on.

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I think we are on the same page here Greg. Big cam with small cubes is going to need more rpm. I think it has valvetrain instability, which will weaken the springs prematurely. Could be a combination of both at this point. I do think a smaller duration cam would help the bottom end some and avoid more gear and maybe get away with his current converter to get that 9 sec slip. It all comes back to whether or not he can turn the needed rpm without the motor laying down.

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First off let me say Thanks for everyone input

Now new springs are n the upgrade list but just trying to figure out this cam deal, so I can get the right ones. the conv is out and will be sending it to UCC for a refreshing and talk to Lenny about spec change. PLEASE don't beat me to bad on this one but rocker are crane gold 1.5s

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Hopefully you have time to research this deal, and figure out what is going to work best for you. Those Gold rockers aren't as stout as some rockers from what I here, and it may take some research to figure out a combo that is right for your deal. The right amount of spring, lobe profile and lift will all come into play. There are a number of guys on this board that have run those rockers, myself included. I didn't run enough spring or rpm to hurt mine though. Good luck with it, and keep us posted.

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Thanks Greg I been working on this combo for about 3 yrs now and I bought all these parts WAY b4 I knew what I was doing lol. truth be told the cam duration thing really has me confused some say I have too much some want it lower just don't know

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Regardless of possible valve train geometry and/ or spring issues, the OP has a big cam and heads that probably want to be spun another 1000 RPM at his displacement.

If he wants to keep the RPM down, he needs to band-aid it with a shorter duration cam to move the torque curve lower.

IMO, he needs to decide what approach to take, first.

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I don't think we disagree here, Brad. As you and I both mentioned, he should have a smaller cam for his combo. I agree he should be turning a lot more rpm than he is, but the question is, why isn't he. That brings up the geometry. But, if he wants the combination to be right, it will need more gear and converter for this cam, or a cam change to work with his existing setup. Either way, he needs to decide which cam he is going with and then deal with the geometry, since valve lift plays a role in the setup. My point is, it needs attention the way it is now, but I agree the combination needs to be corrected first. It will still need the valvetrain set up properly though.

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If he wants to keep the RPM down, he needs to band-aid it with a shorter duration cam to move the torque curve lower.


I agree he should be turning a lot more rpm than he is, but the question is, why isn't he

if he wants the combination to be right, it will need more gear and converter for this cam, or a cam change to work with his existing setup.

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Ok this is where I start getting confused so a smaller duration cam won't let the car rpm as high

Also I tried shifting @ 6700 made no difference shifted lower the car picked up

I'm running a 4.56 now with 31x14 tires what gear ad stall would be right

Also if you can see the pic clear my carb is sitting REAL close to top of hood scoop

Thanks again for all the input

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If he wants to keep the RPM down, he needs to band-aid it with a shorter duration cam to move the torque curve lower.


I agree he should be turning a lot more rpm than he is, but the question is, why isn't he

if he wants the combination to be right, it will need more gear and converter for this cam, or a cam change to work with his existing setup.

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Ok this is where I start getting confused so a smaller duration cam won't let the car rpm as high

Also I tried shifting @ 6700 made no difference shifted lower the car picked up

I'm running a 4.56 now with 31x14 tires what gear ad stall would be right

Also if you can see the pic clear my carb is sitting REAL close to top of hood scoop

Thanks again for all the input

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If he wants to keep the RPM down, he needs to band-aid it with a shorter duration cam to move the torque curve lower.


I agree he should be turning a lot more rpm than he is, but the question is, why isn't he

if he wants the combination to be right, it will need more gear and converter for this cam, or a cam change to work with his existing setup.

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Ok this is where I start getting confused so a smaller duration cam won't let the car rpm as high

Also I tried shifting @ 6700 made no difference shifted lower the car picked up

I'm running a 4.56 now with 31x14 tires what gear ad stall would be right

Also if you can see the pic clear my carb is sitting REAL close to top of hood scoop

Thanks again for all the input

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A smaller cam with a stable valvetrain is very likely to rpm higher than a bigger cam with an unstable valvetrain. The smaller cam will increase the lower and mid range power which will accelerate the car quicker at lower rpm, all else being equal.
The reason, IMHO, that you picked up when your shift point was lowered, is because at 66-6700 is where the springs started to lose control of the valves and the car laid down. The cam wasn't near done yet and the springs were probably not the problem. Improper valvetrain geometry over stresses the springs and they lose control. That doesn't mean the springs are bad. They just can't handle the extra stress that they shouldn't be seeing in the first place. Hey, a ten pound hammer sitting on your foot won't hurt, but that same hammer dropped from a ladder on your foot will increase your vocabulary. Imagine the hammering the valvetrain takes if everything isn't right.

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Have you tried the car without the hood ? you might get a shock when you try your new hood.
Mick

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