It is time to choose a cam for my 350 conversion and I can not decide on a cam. I have read a lot about the zz-4 cam and the lt4 cam. I would appreciate any help with a cam choice that will work with my engine. I am looking for a cam that will work with my tpi and my stock computer( for a little while). I am open to suggestions.

 

There are lots of choices. Let us know more about your car, how it's used, and your expectations. What heads, gears, and intake will you be running? Gotta consider valve springs and retainer clearance before making a final selection. In general if you want to run the stock PROM then you wouldn't want anything with an intake duration too much larger than the ZZ-4 (208 degs @ .050). The LT-4 HOT cam would work great with a manual and decent gears once the PROM is tweaked as long as you have good heads, intake, and exhaust.

 

I am building a 355 to replace the slowly weakening 305 I currently have. I am only now beginning the shortblock stage and nothing is in stone. I have a set of 14096217 casting heads that I am going to open up. I have a 52mm throttle body, adjusable fpr, and a thermomaster chip. I still have the stock manifolds,TPI intake and injectors. I am looking for a good all around cam and springs that I can use with a street car. I don't have the funds for prom burning software, so I need a combo that will work with my combo. I am open to suggestions and grateful for any help.

 

I run the ZZ3 cam. It is great in a street driven daily driver. It will work with stock-type components (prom, torque convertor, gears, etc.). About the only thing you need to check, regardless of cam choice is the lift clearance on your cylinder head. Both the ZZ3 and LT4 have lifts in excess of 0.500. Most stock GM heads have inteference past 0.480.

The Lt4 cam really requires some PROM tweaks to take advantage of the cam. It *could* work find with stock components, but not as well as the ZZ3 cam.

I sometimes wonder if I should have went with the LT4 cam, but all in all, I am very happy with the ZZ3 cam.

... keep in mind that cam choices are important, but so are cylinder heads. A big cam in poor flowing heads are a bad deal. Consider you head selection when looking at cams.

Mark.

 

Since you're running the stock TPI and mildly worked GM heads, you don't want to run a cam with a lot of duration or tight lobe seperation angle. Keep the intake duration under 215 degs @ .050" and the LSA at 112 degs or more. If the heads can handle increased lift then look at the ZZ-4, Accel 74211, and Comp 266HR. If you want to keep lift under .480" then look at the Accel 74216, Crane 2032, and Comp 264HR. These are all hydraulic roller cams.

BTW those stock manifolds are really going to hold you back. They choke a stock engine, never mind once you start modifying. Headers are one of the best bang for your buck mods for our cars. If the choice came down to headers or cam, I'd do headers.

 

headers are coming this summer. I am trying to get the engine together first. Does anyone know what kind of lift I can handle with stock heads? Later on I plan on upgrading the heads, but not in the budget right now. I like the prices on the zz cam, so if will work I will probabaly go with it. I am assuming that I need to run the GM springs matced to my cam or equivalent. Will this cam/springs work with stock rockers? Thanks in advance!

 

If you're using the stock heads, both cams are out the window. Those heads will only support about .460"-.480" lift. You're not putting the stock 305 heads on your 350, are you? If you get new heads, you can have them modified to support the ZZ4 cam pretty easily. I used a ZZ4 cam in my car previously with the stock chip.

 

I am not using stock 305 heads(for many reasons). I will be using heads with the casting #14096217. I am going to modify them with new springs and a minor port and polish until new heads can be bought. What "modifications" to the heads do I have to make for this cam to work?

 

Ensure there is proper clearance for the lift of your cam. Typically the retainer will hit the valve guide at max lift. A machine shop can mill this down with a cutter. Not a big cost item. There are two types of cuts, one will use a GM umbrella seal, the other will need a teflon seal. Go with the GM style one.

Second, ensure you have proper spring pressure. Your cam will have recommendations for closed seat pressure and open pressure. IF you go with the ZZ3 cam, just by the ZZ3 springs from GM. They are cheap. I think the ZZ4 springs are different, so look for the ZZ3 version.

Mark.

 

Ensure there is proper clearance for the lift of your cam. Typically the retainer will hit the valve guide at max lift. A machine shop can mill this down with a cutter. Not a big cost item. There are two types of cuts, one will use a GM umbrella seal, the other will need a teflon seal. Go with the GM style one.

Second, ensure you have proper spring pressure. Your cam will have recommendations for closed seat pressure and open pressure. IF you go with the ZZ3 cam, just by the ZZ3 springs from GM. They are cheap. I think the ZZ4 springs are different, so look for the ZZ3 version. I used number 10134358.

Mark.

 

Actually, you'll want to use the ZZ4 cam springs, as they are better. The ZZ3 springs are the exact same as what came on L98 Corvettes. The ZZ4 springs are the same as the LT4 HOT cam springs, they are stronger and support a little more lift. I didnt like either set and went with some Manley springs, with better seat pressure.

 

just out of curiousity, anyone know exactly what tweaks would have to be done to the prom to maximize benefits of either of these cams, or anything hotter than stock for that matter (or is this a post for the prom boards?) Thanx

 

I have been kicking around the idea of getting edelbrock heads. Would these work well with this cam, or would I still need the different springs? I am looking at the edelbrock performer heads if this helps.

 

i have the same problem. i'm building a 350 for my bird and can't decide on a cam and/or heads. i'm looking for mid to low 13's and i don't think i can get that with stock heads ( can i? ). i was thinking about vortec heads (assembled) and an LT4 Hot Cam. i plan on having it bored .030 over, header-back exhaust, maybe slop intake runners and the rest will be small stuff. it's got a 700R-4 tranny, and i will keep the TPI. so which cam should i get?

 

not sure on the cam or heads to use but mid 13's are possible w/ stock heads and cam.

 

I appreciate all the help guys! I have decided on the zz4 cam. I will have to use the heads I have for now( not the 305 heads) until more money rolls in. Thanks again!

 

I run the Edelbrock heads (#6089) performer RPM. They can handle 0.625 lift, so the ZZ3 is OK. You do have to upgrade to hardened pushrods to work with the guide plates.

The ZZ3 and Edelbrock work well together ... my 2 cents.

Mark.