grzsport

iTrader: (1)

I bought a 1989 iroc 350 tpi. Love the way those cars look. The owner handed me the engine in several boxes. I am having it rebuild but the camshaft is missing. I want to keep it fairly stock by keeping the same block, heads and tpi. I am putting flat top pistons in it and cleaning the heads up. Also going to port match the intake and all that stuff. I have been in search of a cam for the vehicle. Is the zz4 a good cam. I looked at the xfi268 but it does have big lift. I don't want to loose the bottom end power but would like a little more than stock. What do you guys think? Thanks for your help.

Blackdog36

iTrader: (3)

Welcome aboard and congratulations on buying Camaro. Please post some pics if you get a chance.

Your cars computer is MAF (mass air flow) and responds to mods better without tuning than the later computers (MAP). Putting in too big a cam will require a new "tune" which can be done but take some $$ or time. Also you will be limited to so much lift with your heads and roller rocker ratio. You can search on stock head lift for your style heads I can't recall the exact cam but I want to say a crane 2032 or something with similar stats is the most aggressive cam you can run without a new tune. An LT1 or LT4 hotcam might also work. I know the XFI268 will be too aggressive and I believe the ZZ4 cam will be also. Try doing a search on this subject as it has come up a lot.

Getting larger tube TPI runners or siamesed ones will help the 350 breathe better. Bases that flow better than stock can get pricey. If you want an aftermarket base do some searching as I think that the edlebrock one isn't much better if any than stock.

Scroll down to bottom of following link for stock cam criteria. Your cars cam is second from bottom.
https://www.thirdgen.org/mods3

grzsport

iTrader: (1)

Thank you for the welcome. I have searched the forums but just can't seem to get a definite answer on a cam. I called several places like tpis and they recommended there zz9 cam and said I would just have to replace the springs. Comp cam recommended there 08 502 8 cam. Jegs and Summit had other suggestions. All seemed to have too much lift compared to stock (most said it will work with stock heads). I think alot of people just dont know about the tpi cars anymore? The answers are all over the board. I read that the zz4 (zz3) cam would just drop in but also seems to be a mystery. The Lt cams would drop in but some pin has to be ground down. Gm discountinued the stock cam. But since it was missing I thought it would be easy just to buy one that is slightly better than what was in it, not that easy. Any advice is greatly appeciated. If I can figure how to add pictures I will post them.

vetteoz

iTrader: (13)

I had good results with a ZZ4 cam and springs in my L98 but that was with the better (sic ) Vette alum heads

No biggy.
Good for a 305 upgrade; prob not worth the trouble on a 350

Mind you,seeing you don't have a cam;
if you got a cheap (free) one it would work until you did later mods
A LT1 cam is going to slightly larger than stock L98 cam but at .460 lift on not going have to worry about changing springs

305sbc

iTrader: (3)

I work on these heads on a regular basis. It's not the springs that limit the lift as much as the clearance between the bottom of the stock retainers and the top of the valve-guide boss. Having the guide bosses machined down and/or swapping retainers is an easy fix for the lift limitation. For extra high lifts you can also have the spring pads machined a little deeper for added installed height. The stock clearance allows for no more than 0.470" valve lift without some modification.

It is NOT lift that causes a loss in bottom end power, but it is too much intake duration. Keep the intake duration under 215* @0.050" and your bottom end should be fine.
There are several cams out there specifically designed to do exactly what you want, to include the LPE216 cam listed in my signature.
The LPE216 cam actually measures at just 212.5* intake duration @0.050".
The earlier models had the lift numbers posted in the cam-info link above, but later models had higher lift numbers that will require some modifications (as I've mentioned) for clearance. Check the cam you get carefully to be sure exactly what you've got, - don't ever assume with valvetrain measurements.

grzsport

iTrader: (1)

So if I go with a lpe cam then I still need to machine down the guides, correct? Also if I go with a lt1 cam it shows there a 2 different ones (part numbers) one for the 93-94 and one for 95-97 whats the difference is one better? Thanks for the help guys, I feel like I am just spinning my wheels and getting nowhere when it comes it getting engine done because of this one component.

305sbc

iTrader: (3)

The info is here:
http://www.fierolt1.com/lt1_camdata.htm
(watch out for typos)
The stock LT1 cams are about the same, and guide tops don't need machining for 1.5 rockers, but ALWAYS measure anyway.

If the LPE cam you get creates more than 0.470" valve lift with whatever rockers you use, then you need to provide adequate clearance between the retainer and guide-top/seal.