TPIMonteLS

iTrader: (1)

Im contemplating swapping cams over this winter and adding roller tip rockers as well. Im reading up old posts on the LT1 and ZZ4 cams for a swap on a budget and nothing too radical, and peoples opinions seem different. The car is a 305 TPI motor(MAF, not SD) using a 87' TPI setup from a Trans Am. Car is an automatic, stock chip currently and motor except Hooker headers/catback exhaust.

Are both direct swaps, or do either involve PROM tuning/burning, or any thing else like different springs, etc? Id like one that requires as little work as possible besides the cam swap itself but the obvious.

Thanks!

1991tealRSt-topGuy

i believe you want the LT1 cam then

the ZZ4 will require screw in studs and larger springs

Kevin91Z

iTrader: (1)

You will want new springs for sure. What size rockers are you using? If its 1.6's you might have problems with the retainers hitting the valve seals. The LT1 cam with 1.6 rockers makes it .500" lift. The ZZ4 cam will have over .500", and I know that wont work with stock heads.

TPIMonteLS

iTrader: (1)

Forgot to mention:

Car currently has a cam from a 88-89 5 speed TPI car, so Im assuming its a L98 cam basically.

Rockers are currently stock ones.

87350IROC

iTrader: (2)

The LT1 cam isn't much bigger than the L98 cam. So if you're going to do a cam swap go for the ZZ4 with bigger springs.

ZZsmpch

iTrader: (1)

A 350 isn't much bigger than a 305 either. The LT1 cam is much better than the L98 cam. The ZZ4 will need better springs, screw in studs, (recommended for anything over .470) and prom tuning (moreso than the LT1) and you'll have to keep an eye on retainer to stem seal clearance too. If you don't want to reprogram, and $$$ is an issue, you can't beat the LT1. If you think you'll end up going further some day, save the trouble and go with the ZZ4, but be prepared to do extra work. I'm happy with my 305 combo, and it pulls hard to 6K, idles great, and still gets great mileage.

mrr23

i swapped from the LT1 to the ZZ4. picked up .2 in the quarter mile. either one will require the larger springs. and you'll have to cut the spring pockets out to fit either springs. been there done that. click the blue banner. the screw in studs and guideplate are because i wanted to do it. not because i put the cams in. had them both in w/o the studs and guideplates.

ZZsmpch

iTrader: (1)

What head castings do you have that you had to cut the pockets? I'm using the K Motion K-700 springs and didn't need to cut. ( I did port though)

mrr23

well mine is a 350 and its the 083 heads. the 305 heads will have the same small pockets. they will have the 1.250" diameter pocketes. you'll need at least 1.320" mine were cut to 1.470"

TPIMonteLS

iTrader: (1)

Ok, so either cam requires headwork and some sort of PROM tuning.

New question...what if any aftermarket cams out there are a nice improvement on the L98/5 speed LB9 cam? And do they not require PROM tuning/head work?

Lastly, do you think the PROM I have now, which is for a 87' LB9 Auto, needs PROM tuning since it has a 5 speed LB9 cam in it?

Kevin91Z

iTrader: (1)

A cam like the LT1 cam is so mild you do not need a new custom PROM to go with it. I used my stock PROM with a ZZ4 cam and headers and ported Corvette heads. It wasnt until I went to the LT4 HOT cam that I needed a custom chip. Any combination will benefit from a custom chip but the LT1 and ZZ4 cam are mild enough to not need one.