1976 455
-J heads/ bowl blend/ bigger valves/ humps smoothed/ .100 decked off
- L/T headers/3" exhaust
- stock rods/ pistons
- stock manifold/ QJ stock carb
- automatic / 3:73 gears
I was told 220 duration, max .530? It's going to be a street car. Please recommend a part # for a cam. Thanks

 

I do custom cams. Duration will be governed by compression. Lift will be governed by head flow and valvetrain. Let me know if I can help.

 

I was thinking maybe Engle EP-20/22hyd cam to run with my stock valve train.

 

What's the compression ratio?

 

I'm not sure yet! Stock pistons and .100 off the heads is my plan when I pull the heads this winter. I am not sure if the previous owner decked anything when he did the rebuild...

 

Taking .100 off the heads would reduce the chamber cc by about 16, but not sure I'd cut that much.

 

I figure low elevens as a CR. That means a pretty decent size cam. I think a comp cams 286H-8 installed straight up, or a 292H-10 installed 4 degrees advanced would work well given your valvetrain limitations.

 

Low 11s CR???
With iron heads I wouldn't go over 10 on a street car.

 

Uhhh you need to check your math.
The 16cc will raise his compression ratio to about 9.25:1, not low elevens.
A '76 455 would most likely have the 40cc piston.
And yes as 70cutty mentioned, you really don't want to go over 10:1 with iron heads if you're going to run pump gas.

And a general rule of thumb, if you need to advance the cam more than a few degrees then it's too big for the application.

 

If you are just wanting to put a camshaft into a basic stock low compression block without upgrading the valve train and not putting a stall converter into a heavy Oldsmobile. A cam with 215 to 220@50 sounds about right for a more street driving engine. On mild big block engines all camshaft of this size will make around the same power.my personal preference is to stick with a camshaft with 112 to lobe separation on a 106 centerline for idle quality and a more even power band.so it has real good power right off idle.camshaft with lower lobes have more overlap per duration will have lumpy idle and has more part throttle lag off idle until getting up on the camshaft but once its up it will have more tq and power on up.it really about personal preference and how you like to drive.
Cutlessefi could sell you a m/p2 camshaft it looks pretty good with 214/226 on 114 lobes.there is the old white box 214/224 that every one sells that have been proven to work well too.

 

Sorry Grampy but some of your "information" is incorrect. A wider lob sep will spread the powerband as mentioned, but that will lag in the lower rpm range, not the tighter one. And you can't just advance the cam with the wider lobe sep as that will also make the exhaust open sooner, robbing you of even more low end torque vs the one with the tighter lobe sep.

Rule of thumb, a tighter lobe sep will make more peak power and make it sooner in the rpm range than one with a wider lobe sep.
And with such light duration, 215-220@.050, I wouldn't worry about lope or drivability. That's not a lot of cam for a 455 anything.

 

Cutlessefi thanks for the my mistake on camshaft advancement . on low compression engines I always thought if you had less than 160 cranking compression the camshaft was right on the edge of being too big and by advaceing the camshaft 4 to 6 degree would help low RPM power by give better cylinder pressure by earlier intake openings.as for lobe separation on 455 part low rpm part throttle won't matter too much with all the tq but in a low compression 307 or 350 the part throttle is something you can feel by the seat of the pants. A tight lobe always feels a little lazy till it hits the sweet rpm then it hit you hard with more midrange power. The lower the compression the more it feels lazy with a stock converter and higher the gear ratio.

 

I've never heard this before in 30 years if the cam is right. If the cam is too big it's too big no matter what.
I still think you're impressions/ideas are backwards, sorry.

 

-40 cc? That ought to be a crime!

I calculated a 14 cc dish, thus the low 11's CR with a 64 cc combustion chamber. I suggest a piston replacement instead of milling the heads that much.

 

Erson did a bunch of them for awhile. Some grinds were Erson lobes, some were unique to KB.

 

8 out of 10 times a person wants to give there car a little more power they always start with hedders then go straight for a camshaft. They will still have a high gear out back. They have the stock quadrajet jet which is most of the time the idle system is all ready too lean. The dizzy is stock no curve mods. When you put a bigger camshaft it will have less vacume to pull fuel from idle to just off idle about 1800 rpm.this makes a engine lazy because it is way too lean. By adding a camshaft with tight lobes make things worse even leaner.since they still running a 3.08 or worse rear gear there in the low rpm most of the time making the car feel slower not faster. Most people just don't have the know how to re jet and re calibrate there idle passages or recurve their dizzy correctly. I am no expert by far but experience I have. I seen this happen over a hundred times.that x camshaft sucks because it drives like a dog.some carb and curve mods are needed to make it work.
As for wide lobes you smash on the gas there is a steady pull through rpm range .tight lobes it has go but when it gets up into the lower middle rpm range to fell like it has a sudden increase in power more low mid tq. . .this is mostly felt with a tight converter.if you have a loose converter you may never feel it because you flashed past it.

 

[QUOTE=grampy;741889]8 out of 10 times a person wants to give there car a little more power they always start with hedders then go straight for a camshaft. They will still have a high gear out back. They have the stock quadrajet jet which is most of the time the idle system is all ready too lean. The dizzy is stock no curve mods. When you put a bigger camshaft it will have less vacume to pull fuel from idle to just off idle about 1800 rpm.this makes a engine lazy because it is way too lean. So you wouldn't richen it? By adding a camshaft with tight lobes make things worse Why? even leaner.since they still running a 3.08 or worse rear gear there in the low rpm most of the time making the car feel slower not faster. Really? Again why wouldn't you richen it, you normally need to do that with most every significant mod. Most people just don't have the know how to re jet and re calibrate there idle passages or recurve their dizzy correctly. I am no expert by far but experience I have. I seen this happen over a hundred times.that x camshaft sucks because it drives like a dog.some carb and curve mods are needed to make it work.
As for wide lobes you smash on the gas there is a steady pull through rpm range .tight lobes it has go but when it gets up into the lower middle rpm range to fell like it has a sudden increase in power more low mid tq. . .this is mostly felt with a tight converter.if you have a loose converter you may never feel it because you flashed past it.[/QUOTE]

What the hell are you talking about?

Whatever.

 

I don't sell parts ,I work on car and trucks .8 out of 10 people who put performance upgrades on there cars .never touch there carburator even if they got a aftermarket one.the biggest complaint is poor driveabity at part throttle., too low of compression , wrong rear gear ,converter, camshaft, intake,carburator,and poor tune is the cause.most people want a car that's a driver that is fast,that feels fast.
I was just giveing advice to be conservative.lobe center of 106-108 are just harder to tune for a street car that spends 95% under part throttle @ idle to 3000 rpm.less vacume pulling on boosters and idle feed makes it much more sensitive for fuel.on a race car with a 3500 converter idle or part throttle who cares as long as it don't foul the plugs and the jets are right.

 

I think I'm going to hold off. I'm going to save for a pair of edelbrock heads and pistons/rods. I'll just do full exhaust and 3:73's out back. Thanks for all the info!

 

Very good idea.

 

I know the stock TH350 converter stalls around 1600, guessing a low performance TH400 converter would be similar, get a 2000+ stall with the cam Cutlassefi suggested. Spend the head money on a Performer and 750+ cfm aftermarket carb. I like the Qjet but unless you how to modify the idle circuits, an aftermarket carb is much easier to tune more duration and less vacuum.