25thanniversZ

what kind of probs would I expect from installing an lt4 cam in a mostly bone stock new 350 tbi.Would I have to burn chip , chang springs or just stick it in????could I get away with the Lt4 hot cam on the same note?

25thanniversZ

input would be appreciated, only reason im asking is because its a cheap mod.My wife is picking up on cars pretty good now and she is also picking up on the prices of mods, so I gotta make this one count

25thanniversZ

please sombody got an idea??

V8Astro Captain

iTrader: (1)

You'd need a chip. Unless you like terrible running crap.

You'd also need new springs, if your heads could even handle the lift.

txhotRS

someone correct me if I'm wrong, BUT, i was under the impression that there was something different about an LT4 cam, from other sbc engines...

25thanniversZ

I was under the impression that the lobe seperation was about the same and being a roller moter the cam itself should slip right in.The tbi 350 is a new crate motor, late model roller motor,cast heads ect.....just stock

8Mike9

What V8Astro is saying, is could be the valve giude bosses need to be machined for the higher lift cam.

Some of the later model GM cams (not sure which ones) need to have the dowel ground off a bit.

All that said, might be worth a trip to the TBI board to see whats up.

Best to mention the head casting numbers as well.

25thanniversZ

Oh, I just keep seeing people say that you just stick the cam in with new springs and maby a custom chip

dimented24x7

iTrader: (2)

i personally think the LT4 hotcam is going to be a little to 'hot' for a mostly stock L05 350. The sworl port heads will never be able to flow enough and the tbi will really choke it. I put my vote in for a good set of aftermarket heads and the zz4 cam. With some tuning that should pretty much get you to the outer limits of power production with tbi.

25thanniversZ

all I have is an adjustable fuel pree reg,helix 1'' tbi spacer,accel dist,wires,plugs,coil, tbi mods(which didnt seem to make much of a differance),headers,duel 3'' exhaust, th350 tanny,3:73 gears,cold air induct. Money went in buying the crate motor, so I dont really have enough to go and get the heads like I would really like,but I need more top end cam at the moment,but like everybody I want the highest lift cam with the least amount of mods

25thanniversZ

ok so the zz4 cam is a better go???I can deal with s--ty running for the moment untill I can get a custom chip or whatever,if I can just stick an lt4 hot cam or zz4 cam in it without head mods and chip tuning,obviously gott get the springs though...right?????????

dimented24x7

iTrader: (2)

both of those cams have alot of lift for a stock head, even the LT4 if your jsut using the 1.5 rockers. You definatly need to check clearences and possibly have the guids machined down. What kind of heads do you have? Id still look into a good set of aftermarket heads if i where you. With the work that will go into making the stock ones work you could ahve a good set of aftermarket heads for the same ammount of effort.

dimented24x7

iTrader: (2)

if you dont have winaldl or a scanner, you shouldnt drive the car after the swap. Without knowing how the fuel situation is, you could be unknowingly killing your motor as you drive it. And go get he prom burning equipment and burn a prom yourself. Dont rely on someone else to do it for you.

85rocker

LT4 cam no problem it will fit your stock setup NO problem that includes factory chip.

LT4 HOT forget it your SD system will barf and puke forever.

Lift clearance is NO problem even with 1.6s on the LT4 HOT.

Might do new springs if the old can't be trusted.

LT4 is a better choice for the TBI than a ZZ4 or HOT.

ZZ4 - Hyd. Roller - 208/221 - .474/.474 1.5 rockers
LT4 - Hyd. Roller - 203/210 - .476/.480 1.6 rockers
HOT - Hyd. Roller - 218/228 - .525/.525 1.6 rockers

25thanniversZ

thats the whole point...I aint got the cash to go out an get new heads, my wodd went on the new crate motor,yes I have a snap on scanner, and who is right???LOL also is the lt4 cam going to give it a noticable lope or what???hope not ,dont want people trying to race me at every stoplight because it sounds like it got a pair, but I would like it to be a good stepping stone if I ever could get a good set of heads, but the motor is new stock 350 roller motor cast heads ...aint looked yet to see exactly which roller motor (to dark out) but it for sure has a roller cam...I saw the lifters when installing tbi intake...heres my part#12513151 ENG-5. description 9801 for what good it is
LO5 probably but aint looked on the block yet

dimented24x7

iTrader: (2)

nope... the cam i have has similar duration and lsa and it wont lope a bit. As a matter of fact, it will still sound the same as it does now. My setup is pretty close to what you will ahve if you just get the LT4 cam (assuming youll be using the 1.5 rockers) and it makes around 230 HP and the ecm dosnt have too much trouble with the cam but some tuning would help. Not bad but better then it was with the crap cam that it came with. The LT4 will be very friendly to your setup. Wont make tons of power with the stock heads and tbi but it should give decent performance and you wont have to touch the ecm.

25thanniversZ

as in the ECM...are you talking about the 305 or the 350 ECM, I have the 350 modual and prom with the 350 injectors?I can go rob a cop caprice prom if necessary

dimented24x7

iTrader: (2)

the 350 prom and 55 pph 350 injectors should be fine. I still have the 305 L03 prom in mine. One of these days ill get of my **** and burn a prom for it.

25thanniversZ

ok since I have the 350 ecm and stuff can I run an even bigger cam than the lt4 with my stock motor?

JesasaurusRex

iTrader: (3)

The zz4 has .476/.510 lift just correctin ya a lil since i own 1

flyway190

As far as ZZ4 cam(1500-5500 rpm) vs. LT4 HOT cam(1500-6000 rpm), would you really want to push that bottom end over 5500 rpm? It's not weak, but I'm sure GM didn't have those kinds of speeds in mind when they built this engine.

25thanniversZ

Flyway I got my goodwrench at Youngs Chevrolet, so only 500 rpm's dif huh?

flyway190

Young Chevrolet in Dallas? I got mine from Scoggin-Dickey, came out to $1700 total.

LT4 HOT cam info
ZZ4 cam info

You might also look at these from Comp Cams:
08-501-8
08-500-8

25thanniversZ

ok, the info on the zz4 cam I just read said not computer compatible??what gives?? oh flyway I gave $1500 for mine delivered to paris.....my cousin is parts manager there

flyway190

I think some people have gotten the ZZ4 cam to work with TBI, do a search to find some info on that.

I was wondering who in their right mind would pay the $2400 or so they wanted for it, not including any shipping or taxes. They have a HUGE parts warehouse compared to the other dealers around here though!

Sitting Bull

OOOoooooohhhh, I wouldn't attempt anything with a lift of over .460 with stock heads and those LO5 swirlport heads just won't cut it anyway

25thanniversZ

thats why im in love with this tech board:hail: so many aspects and points of views some wrong...some right....but always makes ya look at every angle that you would have never thought of

Sitting Bull

The LT4 Hot cam is completely out of the question without machining the valve guides. The other two will mechanically work OK but only with 1.5 rockers.

As for how much cam a TBI will tolerate, I'd talk to the folks on the TBI board. Good luck!

25thanniversZ

the info I read about the zz4 cam is that it was not computer compatible????is this bs? the only thing I can do for the ecm is throw in a caprice cop chip thats sitting in pops junk yard...no burning capability and aint got the $ for the software or the know how to use it...got just enough for a cam and gasket type things

Sitting Bull

Yes, the ZZ4 cam is from a carbed engine thus it might be a handful to make work. Basically, the problem is fuel injection demands a wider LSA (lobe seperation angle) than carbs, in order to provide a strong vacuum signal for the computer. Thus you should generally not use any cam with less than 114* of LSA on fuel injected engines. I'll bet the ZZ4 cam is no more than 112*, borderline for fi.

As for chips and such, it is all voodoo to me, too. That's why I'm so glad I have a carb on my 86 305. So much easier to deal with--not to mention less expensive

flyway190

I suppose they just said that it isn't for use with computer controlled engines so people wouldn't call their tech department asking them how to make it work with their computer, or maybe they want to make it clear that you can't just drop it in with a stock computer and expect it to work.

25thanniversZ

yep, thats why most of my other play things including the toy for the wifey are carbed (though hers is just loud to make her think she's got a car with a pair)damned if I build her a runner with the way she drives

flyway190

What I find strange is that the cam that comes with this engine has a 110* LSA (according to Pace's catalog). Are larger LSA's only required for cams with high lift and long duration?

Sitting Bull

Carbs can cope much easier with a low vacuum engine than fi engines. Thus 112* is generally the widest LSA you will find made for carbs.

It is the overlap between intake and exhaust valves, the return of exhaust fumes into the fresh fuel charge, that gives a fi engine fits. This extra duration, as you guessed, drops the vacuum significantly. As you widen the LSA this overlap decreases. FI just wants to see lots of vacuum, unless you know how to modify the chip properly.

25thanniversZ

think I would have a better chance with a cam if I put a cop caprice chip in?

Sitting Bull

I just don't know. But I think the trick is to keep the new cam's duration fairly close to what the original cam had.

25thanniversZ

well I do thank you for your time on this thread, guess i'll go back to my head thread now