I have a 305 TPI with stock heads (stock springs, retainers, etc).

Which cam should I swap in and what work is involved?

Is the LT1 cam a direct swap with no work (do I need to change the springs?)

Can I run the ZZ4 cam (what work do I need to do)

Need advise...........not too mechanically inclined.

Thanks..........

 

You should change valve springs with either cam. Eliminating the stock exhaust valve rotators is a good idea.

The ZZ4 probably has too much lift for your stock valve travel. Pull the heads, have the guides cut for positive-type valve stem seals, verify travel of each valve with the retainers you're going to use, reinstall.

 

Can I just change the stock springs with new ones, drop in the LT1 cam and be done?

The ZZ4 swap sounds like a lot of head work ($$).

 

That's one of the reasons it's popular.

Do both springs and retainers.

 

Is one spring better than the other?

Is there one you would recommend? Do you have a part number for spring and retainer?

Thanks

 

Another thing to keep in mind if you're going to use an LT1 cam. Try to get one from a 93 or 94 LT1. The 95-97 LT1 cams have a longer dowel pin than our cams, so you'd have to cut it shorter. The pin on the 93-94 cams is the same length as ours. They used the longer dowel pin when they switched to the vented style opti-spark distributor in 95.

 

You can drop in some Comp 981 springs in place of your stockers for a good mild performance upgrade. You can still use your stock retainers and locks (yes, even the exhaust rotator/retainers). If you choose to replace the rotator/retainers with standard retainers you'll have to shim the exhaust spring by about .060" to bring the installed height back down to spec.

The Comp 981s will handle more lift than your heads can (stock/unmodified heads usually poop out around .470" when the retainer hits the guide seal). I've used the 981s in mild roller cam applications several times and they work just great.

 

Thanks Damon,

Do you have any recommendations for retainers and locks if I decide to replace them?

 

What about dropping in an LT1 cam and swapping in some LT4 springs. Do they require any mods?

 

No. I'm running them.

 

What is the difference between 7 and 10 degree retainers?

Will both fit an LT4 spring on a stock head?

Is it that both will fit on a head with factory valves but that if I buy 10 degree retainers I have to also buy 10 degree locks as well?

Just trying to clarify before I purchase.............

thanks

 

Retainers & keepers have to be the same "degree" type. Either will fit the springs, heads, & valves.

 

Thanks for your help.

I'll probably go with the ZZ4 springs and matching retainers and locks from GMpartsdirect.com. Can't beat the price. It's half what I would pay at Summit for the comp cams components. I'll take the $$ I save and buy a new timing chain (double roller).