1991camaro_z/28

Hey guys, I have a dumb question, can I use a cam off a carb car for tpi, or do I need special efi cams for the 350 tpi?

Thanks in advance

Abubaca

iTrader: (3)

Are you asking if it will physically work and run, or are you asking how optimal it will be?

1991camaro_z/28

Both.

Is there anything that will hinder preformance by using such a cam?

Abubaca

iTrader: (3)

The cam has no idea what's on top. ...meaning there are no special EFI gears or lobes or anything that a computer would need to properly run. I just got a custom grind roller camshaft, and with the necessary lifters, installed it into a '79 block. I'm quite sure it had a carb originally, but I'm throwing a TPI on top.

As for performance, once you establish that it WILL run with no problems....it depends entirely on WHAT cam you have. As a rule, TPI makes torque down low at the expense of power up high in the RPM range. Now a carb, depending on what size carb on what size motor can handle a LOT of different scenarios, and ideally you'd choose the cam accordingly. .....so without knowing what size carb you had, and what size motor, ....and of course that's all assuming the cam was properly selected, it's really hard to say how it'll perform with TPI.

It's not a dumb question at all, but we really need more pieces to the puzzle. Do you HAVE the 350 TPI now? ...but no cam? ....what cam DO you have, and where did it come from? assuming this is a budget street build?

1991camaro_z/28

The car right now is a completely stock 350 tpi, and I found a cam out of a third gen, that was in a carb 350, bored out to a 400cid sbc. The brand and specs are unknown, however it is a roller cam. My understanding is for the 350 and the 305, anything after 87 should be a roller, meaning my car, a 1991 camaro 350 tpi should be roller. I have not pulled the motor apart to verify though.

Abubaca

iTrader: (3)

Yeah, always wanna verify, but yes, a 91 TPI would've been a roller.

OK, so without knowing what the cam specs are......I'm going to assume that a carbed 400 most likely is using a cam that is WAY too big for a 350 TPI. ...unless of course, it was WAY TOO SMALL for a carbed 400!!!! ...likely in fact that even though it's a roller cam, it'll push the valves way too far and cause all kinds of valvetrain problems. Again, can't be sure, but I think it's safe to say it's not a good gamble to take.

I'm not going to get into a performance debate, and with any cam swap there's tuning to take into consideration, but look at cams like a LT1, Crane 2032 or zz4. ....and of course there are others. They're all fairly mild, but can give you a good bump. ....again....remember tuning is always a good idea, and can be even MORE necessary with the 90-92 SD cars.

Are you looking for a bump in performance? ...do you have full exhaust/headers? Shift kit? torque converter? ...these can all make pretty big seat of the pants increases to an otherwise stock set up.

1991camaro_z/28

Thanks for the advise, I just happened to find that cam cheap, but I will not buy it considering the unknown. The primary purpose was mearly to change the idle, and increase top end torque slightly. The car is a daily driver, but I take it to car shows a lot, and was looking for a cam to give a rough idle. The rest of the car is stock with the auto tranny.

Abubaca

iTrader: (3)

That choppy cam sound come from the overlap of valve timing. Intake valve is still open when the exhaust valve starts opening. This is beneficial for upper RPM power, but down low causes turbulence. Not great for low end torque, but it definitely sounds awesome! I'm on board for both the power bump AND the cool choppy sound......except for one thing. One a stock 350 TPI....it's not gonna help, and may even hurt. The heads themselves will hold you back for sure, but even worse is the stock TPI. It'll start choking the engine long before the cam has hit it's stride. ....It's just parts mismatch.

Now, only speaking from my experience, I had a stock TPI, with stock heads, headers and exhaust, and I swapped in a zz4 cam. It had ever so slightly enough chop that car guys could hear it, but most people would just think it was stock. I got a noticeable, but not crazy performance increase, and I was happy. That was over 10 years ago, and I wouldn't put for the effort for a cam only swap again, BUT....that's purely my opinion. PLUS...on a car with Speed density like your 91, and not an 89 (like my car) with MAF...you'll definitely need tuning. Depending on where you live and who you know, that may or may not be an issue.

I don't know your mechanical ability, your budget, your age, how much time you have, if you have another car, yada yada yada, but for ME....i'd either plan to do a little more work than just a cam......OR.......I'd probably leave it alone. BUT....this is an awesome site...and if you decide to do anything....regardless of what it is, this site will be here to help!

1991camaro_z/28

Thanks. Any heads you recommend? Also I was looking at possibly the comp thumpr cam line. If I change the heads and possibly the intake, would that cam line give me good results.

Fred SS

iTrader: (3)

For tpi, I would recommend the AFR 180 head. Not too big, not too small. I'm currently running the trick flow 175 heads and I think their a little too small, but still a good head for street. I like the comp thumpr cam line, but if I were buying a cam now, I would choose a Voodoo cam. I've spent allot of time looking at cams for tpi and the voodoo cam line has always been near the top of street cam choices.

1991camaro_z/28

Thanks Fred SS. I will defiantly look into the voodoo

Abubaca

iTrader: (3)

What's your budget for heads? ....AFR may very well be the best you can buy out of the box, but they cost. I went with RHS. For the record, for a 350, I like those Trickflow 175s too, but haven't actually used em, and they might be small, especially if you plan to upgrade parts later. LOTS of great choices out there.

The Thumper's are similar to the Lunati Bootlegger's, in that they have a good lobe profile, but add valve overlap (measured in degrees of duration) to get that aggressive sound. ....and the same principal still applies. For a TPI...it's just not ideal. ....and of course I like Voodoo cams. Just bought one.