dangerousd89

a buddy of mine gave me a cam he never used.. the box is a little worn so here is all the info i could read. cam lift .298, valave lift and exhaust .447 duration 291.. is this a decent cam..ans is it compatible for computer controlled cars.. i dont really now how to choose cams and what info you all can give me is appreciated

Stekman

Well first off, what type of cam do you need? hydraulic flat tappet? hydraulic roller? If you can see the back of the camshaft, you will see information that has been scribed in. This info usually includes the part number, the intake lobe profile, exhaust lobe profile and the lobe seperation. What you are looking for is stuff that resembles this (this picture is of an Isky cam, your of course will differ, but the general writing should be the same)

If you can see the bottom of your camshaft, find out what is written there and we can work from there.

That duration versus lift figure appears to be typical of a hydraulic flat tappet cam. On top of that it looks like it was designed to compatable with factory equipment. Retaining factory spring clearance and such. It is hard to give an accurate prediction as to how the cam will act and, overall, cooperate with your setup without knowing the intake profile and the lobe seperation. The duration you supplied looks to be the advertised, as no .050" duration with that little amount of lift exists. Without knowing the .050" duration (duration from when the tappet is at .050" of lobe lift both opening and closing ramps), it is hard to say much in comparison to other cams. Again, going to the rear of the cam, most companies either put a part number (if its an off the shelf grind) or the lobe profiles that were used on the intake and exhaust. If you get them, we can try to find specific seat to seat and .050" duration figures as well as lift and lobe seperation.

You have an EFI car so for your case, you will want to have about a 112-114 lobe seperation. MOST off the shelf performance grinds are ground on a 110. However, once you start getting into the far smaller ranges, i.e. the ranges used for torquer vehicles and stock replacement or performance grinds meant to be compatable with factory equipment, it wont be unusual to see cam grinders switch to a 112 to 114 lobe seperation. But generally, to correctly size up a cam the folling data is needed (the data you have provided was filled in(:

Advertised duration int/exh: xxx°/291°
duration at .050" tappet lift: xxx°/xxx°
lift int/exh (generally 1.5 ratio in sbc's): .xxx/.447
lobe seperation: xxx

So as you can see, theres quite a bit of info missing before we can go about saying whether or not this is a good cam. once again, if you can see the rear face of the cam, get the info off there and toss it up here and we can work from there.

dangerousd89

thanks for the info..ill be picking up the cam on tuesday so ill get all the info i can

ede

as cheap as cams are i think i'd pass on any cam i wasn't 100% sure of

RB83L69

That sure does sound like a "151" cam; 291Ā°/291Ā° advertised, 221Ā°/221Ā° @.050, .447"/.447". If so, it's the old "350 HP 327" cam.

By today's "HP "Rating" methods, that cam would make about 185 HP in the motors it came in. It's definitely not computer compatible. Above all not with fuel injection.

What it will do in a motor, is it will give it a little bit of "lope" sound at idle; it will idle terrible, especially with an auto trans; the bottom end will be real soggy, because of all that "advertised" duration, which basically is just making the valves "leak" unnecessarily for too much of their cycle; it will seem to wind up forever, because it never really has a torque peak; and when you're all done, you'll end up with a 16-second car with no power and horrible gas mileage.

It is one of the worst cams of all time. I would not consider it to be a decent value even for free. Because then I'd have this garbage I'd have to throw away. Basically, someone ruined a perfectly good cam blank by putting that grind on it.

But, find out for sure what it really is, before jumping to any conclusions; look for a mfr, part #, etc. However, if that's all the info you've got, I'd recommend not putting it in any motor you expect to run good. Follow ede's advice.

dangerousd89

rb you hit on the nose thats exactly what the cam is.. its magnum brand..i had to call my buddy whos givin it to me to get more info...now that i know its a pos... what would you guys recomend on a 350 tbi... i really want good input in cams since this is most definently my next project.. within a week or two.. so guys fell free to give all advice and part numbers..just as a recap...350 tbi.edelbrock performer intake..holley 670 tbi, hooker super comps into a high flo cat and super 40 series flos... the heads are stock till ican save enough for the sr tourqers...

Stekman

Well, what year block is this? That will determing whether or not you need a flat tappet or a roller tappet cam. Either way, roller or flat, Comp and other cam grinders such as Crane offer versions of their cams that are intended for computer controlled cars. They usually end up being the same lobe profiles, or at least, very similar. except they are ground on a larger lobe seperation. The smaller selections of CC cams (the ones with the smaller durations) are generally ground on 112° LSA, whereas the larger durations are ground on a 114° LSA. Considering as how your setup is under the category of intake/headers and no other modifications i would look into a Comp Xtreme Energy grind. The ones with the powerbad of 1200-5200 +/- 100 or so on each are the ones you should be looking at.

You have stock heads and mentioned upgrading to S/R Torquers in the future. You will want the dual pattern cam design then. The dual pattern increases the exhaust duration (generally) which compensates for the poorer flowing exhaust ports of SBC heads. Even though the Torquers are aftermarket, they too, can benefit from the dual pattern design.

I pointed out the Comp versions. While ou need to determine whether or not you need a roller or flat tappet is still undecided. Also, just because i mentioned Comp, don't rule out Crane. Look at their grinds Use the .050" duration when comparing the grinds considering as how Crane considers advertised as .006" tappet lift and Comp is .004" IIRC. Make sure you look at the LSA. 112-114 is the range you are shooting for. If you visit Comps site, take a look at the 12-249-4 and the 12-256-4 (Xe249h and Xe256h, respectivly) grinds. Those are the cams you will want matching figures on. Again, if you have the roller setup, you will need a roller version, which do exist.

dangerousd89

thanks for the info. the block is 89.. i have no idea if its roller tappet or flat. like i said i am barely learnig about cams.. so if wou dont mind what do the abbreviations stand for ...lsa,IIRC?? the more i learn at this site is wild..i know thw basics lift, exhaust..some other little stuff. also what about isky cams..i heard those are mainly for high hp engines. so would i rule them out...

Stekman

ok. Unfortunatly, short of looking up the casting code and whatnot, the only way to TRULY determing what cam you need is by looking in one of 2 places.. Either pull the intake and look for a little spider. I dont have a picture handy, but if you pull the intake and see some long flat piece of metal with 8 "arms" coming off of it, you have a roller cam. 86 was the changing year for the F-body, i dont know if that means change over in the trucks or not. But i would think that it would point out you have a roller setup.

As for cams, the abreviations are simple. LSA stands for lobe seperation angle. This is the angle between peak lift on the intake lobe and corresponding exhaust lobe. The smaller the angle, the closer the lobes are together. "IIRC" is just an abbreviation for "if I recall correctly."

Isky cams. I have one, as you saw in the picture. I love it and im not even running it yet. Something about Billet Steel gets me all tingly. Generally Isky is geared more for race, as you stated. However, they do make street profile cams. It is just generally their more costly than Crane, which is more costly than Comp. For your situation, and most situations encountered on this board, Crane and/or Comp grinds are generally the most commonly voiced. There isnt to much opinion floating around on Isky. (well there is, just not near as much as Comp or Crane or Lunati)

dangerousd89

i have no spider..when intake was removed.. i also removed the valve covers a nd put new ones. if it was roller wouldnt there be roller tiped rockers at least.. but definitly no spider..as for abreviations im still not that online savvy i think..

Stekman

When someone mentions roller camshaft or a roller valve train, they refer to the type of lifters.

As you can see, the roller lifter on the left has a roller built in that allows it to literally 'roll' on the cam lobe. The lifter on the right is flat tappet.

Also, a roller block is machined differently.

As you can see there are 3 little 'towers' along the center bottom of the lifter valley that have been drilled and tapped. These 3 towers are what the spider bolts to.

That is the cam retainer plate that prevents a roller cam from walking forward and pressing the cam gear into the timing cover.

Thats a factory roller cam design. As you can see, the stepped nose design fits snuggly into the cam retainer plate. Those elements, in combination, make for a roller cam/block.

The hydraulic flat tappet, or pre-86 cam/blocks have none of that. THey have flat faced cams, there is no holes that have been drilled and tapped anywhere, there is no roller tappet.

dangerousd89

thanks for the good info stekman.. now that we have determend that i do not have a roller set up what is the biggest cam with a good lope that i can put and not really mess up the computer controlles..all open suggestions welcomed ..thanks for all the good info guys.:hail:

Stekman

Well, the stock converter and factory chip are the limiting factors right now. Most cams that have that classic choppy idle wont go over too well with the computer. From Comp, either the 12-249-4 or the 12-256-4 would be my choices The specs for them are:

12-249-4:
Specifications:
* Advertised duration: 249 intake/260 exhaust
* Duration at .050 in.: 206 intake/212 exhaust
* Gross valve lift: .434 in. intake/.444 in. exhaust
* Lobe separation: 112 degrees
* RPM range: 1,000 to 5,000
* Works best in stock throttle body, Crossfire, or carbureted engines

12-256-4
Specifications:
* Advertised duration: 256 intake/268 exhaust
* Duration at .050 in. cam lift: 212 intake/218 exhaust
* Gross valve lift: .449 in. intake/.456 in. exhaust
* Lobe separation: 112 degrees
* RPM range: 1,200 to 5,200
* Works best in unmodified TPI 305 and 350 engines:

From Crane, the Powermax 2030 wouldnt be so bad. Specs are as follows:

* Advertised duration: 264 intake/274 exhaust
* Duration at .050 in.: 204 intake/214 exhaust
* Gross Valve Lift: .423 in. intake/.446 in. exhaust
* Lobe separation: 110 degrees
* RPM range: 1,500 to 4,500
* For use with 1981-87 TBI 350 engines only.

Again, when comparing cams, use the .050" duration.

I have personally run the cam that is one step smaller, the 2020. It is designed to run on the factory setups of TBI and Crossfire. There was nothing WRONG with the cam, it did its duty and produced tq down low and some good midrange power. It just fell on its face in the upper rpm band.

Are you MAF? If so, i would stick to the smaller selection of cams that ive listed. Unless you get into PROM tuning, your ECM will do some strange things and, in the end, will effect the overall usage of the vehicle. Its a lot to do with the fuel curve and how a cams needs will alter the fuel needs. Basically, the smaller cams are ground to be compatable with the factory fuel curves whereas the larger cams need tuning to compensate on the fuel curve. I know running the larger cams on the factory curve effect cold starts, i am not sure as to what else it will effect. But generally, to get the most out of the larger cams, PROM tuning is required. This is why i run a non-cc carb.

dangerousd89

well as for the torgue converter im saving to get a decent 2500 stall.. chip wise i dont have a clue how to even begin to burn my own chips. ive looked at that section and got a headache. i had already installed a stage 2 jet chip.( i already know how guys at this site feel about those. but it has worked fine for me) as for furl delivery i am running the 670 holley tbi and getting to holley high volume fuel pump soon. and what does maf have to do with cam selection? maf= mass air flow right....

Stekman

Yes, MAF is mass air flow. And while the sensor itself does not have very much to do with cam selection, the corresponding ECM, does. It is all in the fuel curve per RPM/MAF reading. (i think). Im not a ECM/PROM tuner so i couldnt tell you the specifics.