The Stovebolt Site Forums The Shop Area Engine Shop 3/4 race cam

Just got a good deal on a new Wolverine 3/4 race cam for a 235 with solid lifters #968.
Does anybody have experience with this cam and what is the difference to the M4F or 261 stock cam?
I want to put it into a 261 eventually.
What kind of performance can I expect together with fentons, dual 1bbl carbs, 848 head, closed drive shaft and 3.55 rear?
Specs are:

Duration 291 I 275 E
Cam Lift .279 I .273 E
Valve Lift .405 I .387 E

Clearance .006 Hot .016 Hot

I appreciate any input, Thanks.

A 261 can stand a hotter cam than a 235, so it should be still fairly smooth on a 261 but give some good breathing.

Wow, those are some big duration #s. Make sure you've got decent compression, as the cam may bleed some cylinder pressure. Compared to a M4F, the duration on this cam is longer, but valve lift is smaller. I'd really like to know how this cam would run.

M4F is a single pattern cam, 210 dur @ .050" with .420" lift. I assume the Wolverine duration numbers are adv duration, multiply adv duration #s by .85 to get duration at .050".

Its also weird that intake lift and duration are larger than exhaust numbers. Usually its the other way around. This may be an old wierd grind, meant to build cylinder pressure.

chip

Your in CA...... Me too
Wannas race for pinks?

I got this old green thing.Never seen the back side of a Chevy

Seriously You are geared too high and will have no vacuum at 60-70mph a cammed 235 just doesn't have a lotta torque.Your not likely to get the passin' punch you want

J.H. Proffit's Old Green Thing (see the mower handle sticking out of the back?)

[img]http://www.directcon.net/gmc248/Proffittstrk.jpg[/img]

Just funnin' ya Jim; I know you hate MOWERS!!!!

Chip, remember that intake has to suck the air/fuel mix into the cylinder and the exhaust has pressure to help it out.
Now this is a different story when there is a turbo or super-charger involved

I would think that this cam would produce a heck of a lopy idle, with duration #s like that. The lift is rather low comparatively speaking. Those numbers seem to be top-rpm friendly. For comparison, my low rpm-high torque cam's specs are

duration - 194I/204E at .050
valve lift - .464I/.490E
lobe centerline - 110 degrees

This cam gives a very smooth idle on a 292 (or so I've been told, mine is together but have yet to be fired). But I'm only concerned with off-the-line torque. I'd be interested in knowing how yours runs once you get everything together. What's the lobe center angle?

-ftyler

I knew JH talked tough, but was a fluffy bunny after all. :p

The stock 261 cam is the same as the Corvette 6 cylinder cam amd close in specs the the Howards M4F.There's a lot to cam design, lift, actual duration, lobe separation and how quickly the valves are lifted off the seats. The M4F has short duration but lifts the valves quickly, good for power in the 2000-4000 rpm range, great for vintage motors like a 235-261.The M4F advertised duration is 236 degrees.Advertised duration includes the clearance ramps used to take up valve train slack before the cam gives real lift.In reality , these engines,especially the 261, have heavy moving parts and trying to spin them up high is not always the best idea.That Wolverine cam with it's high advertised duration may kill the low end and you could wind up with a lumpy dog.Or it may be just fine, depending on your driving style, carburation, engine mods and your tuning ability.

Thanks for the helpful replies. Very interesting.
Sounds like this cam would be a bit too hot for the 235 in a daily driver.

I got it for a 261 block, I am still looking for.
I was just curious, what the difference would be to the stock 261 cam or MF4 in that block with a 848 head, fentons and dual intake and 3.55 rear.

What I am looking for is to be able to accelerate faster from a dead stop and maybe climbing my local hills with more power and ease.
I am not sure if freeway performance requires an all together different setup...?

I'm not looking to impress others on the road.
Just like to get the most out of a 50s style rodded 261 for my driving habits.

Thanks again for the input, I learned so much from you guys already since I joined.
My beloved truck certainly is happy about all the improvements lately.
I bet it didn't think it would be in such good shape again, after all those years.
We sure appreciate that there are still knowledgeable, caring folks out there.

Thanks Tony for the info.
I just typed in my last reply when your post came in.

Sounds like the stock 261 cam might be just fine with my setup.
Let's see what kind of 261 short block I will find.

That brings up another question:
Is it OK to break in a newly rebuild engine with one cam and then maybe changing to another shortly after or even during the break in period?
Sounds like asking for trouble and I should make up my mind before break in.
In that case I probably go with the stock cam, after all.

I have a 37 pu and a 51 pu, both are powered by 261's. The 51 engine is more or less stock, the 37 has a M4F cam,small 4bbl, Fenton headers, and more compression,both have the same rear end gears.The 37 is probably 400 lbs lighter, but what a difference in performance.The 51 runs great, good pulling power, but the 37 pulls the same at low speeds and far better at mid and high speeds , the engine is far more free reving.It might be better to choose the right components from the beginning, but the stock 261 cam should be fine.Check your 261 cam casting number to be sure it is a 261 cam.

Cam Rules!!!!!

More duration less torque

Increase lobe centers less lope

Increase lift more torque

More intake more torque

More exhaust more revs

The bigger around the more HP

Exhaust valves are smaller than intakes cause you can push more air than pull

Gmc's are faster than Chevy's cause they are bigger and longer.....and you can get a 12port cross flow
head....NEW

If I was standing in front of Chevy I'd have a Turtle suit on!!

AND Tony??? When was the last time you drove either one a those trucks really fast??

NOT WITH JOY LOOKIN'

Ftyler, that cam of yours must be the same as mine. Blueracer #WG-1178

ADV. DUR. 260 I 270 E
.050" DUR. 194 I 204 E
cam lift .265 I .280 E
valve lift .464 I .490 E
lobe centers 105 I 115 E

I am running it in 250 with automatic transmission. It has some lope to it but not much. Sometimes I think it just might be the carburator and not the cam. I never had a stock engine to campare it to. It's not going to wear the tires anytime soon, but has pretty good pickup to it. I don't have the kick down switch hooked up, but haven't really needed . Just push on down and away you go. I still have the stock intake and exhaust manifold with 3.42 gears.

I'am going to sneak down to the strip one of these days just to see how fast the truck is. I suspect the mid to high 16 second range. Joe

I'm only here cause Z went to Poland to spend Easter with her family....leaving me alone,so bored
I'm even reading this stuff!

Next week she's back and I'm gone.

Look close at the front a that truck.....You short motor guys only get to see the tailgate

I am glad to see that there are still a few truck questions here

Any you other guys got a bunny suit?....no fair making it outta tin foil!!!

JoeH's cam looks more typical- More lift and duration on the exhaust to help it breathe, 105 IC, likely a 110 LSA. The tighter the LSA, the peakier the torque curve.

Well JH, its good to see ya again, even if you're a PITA, you funny bunnyman. :p

chip

Yo Joe H!

Probably the same grind, but slightly different cam. My fuel pump lobe is in a different location from your 250, unless you're running an electric unit. You probably don't have enough carburetion and air for that cam. I'll have plenty, if not too much, with an Edelbrock 500 cfm 4 barrel.

Since I've been told that the same cam grind acts "milder" on a larger displacement engine I'd expect the cam to be rather tame on my 292, with no lope and excellent idle quality. I have 36" long, 1 3/4" primaries on the exhaust. That plus the cam grind plus the added intake should make it pull really good off the line. At least I'm hoping so. Might even turn a tire (on gravel)