If we took out the tuning aseptic of this question and looked directly at the heads
with pin studs, and springs adequate enough to take the lift with a 1.5 ratio would there be any clearance issues on a 187 casting running a intake lift of .474"and an exhaust lift of .510", also i read that there are springs that are "stock" drop ins that take 500" of lift and up by stock do they mean there is no machining?

 

anyone?

 

Nope not even close, I've never seen any stock head take more than .480 lift without touching the seal. I have seen dirt track motors ran with .500+ lift cams by simply leaving the seals off, which really isn't an option on a street car.

The time and money spent on getting the heads to take that kind of lift is going to make a head swap very appealing. On top of that the ZZ4 cam is a bit big for the power band that the 187 castings like to run in. If you can swing it, a vortec swap is the way to go. If not you may look into the LT1 cam as it's as big as you can go on the stock castings and matches the head design well.

What are your goals for this motor.

 

if you want to be able to run a zz4 cam on the 187s go find some manley parts. first get the manley springs 22410 i believe is the number they will fit stock and will allow the lift of that cam. now to fix that clearance problem get manley 23652 retainers which are +.050 clearance. wallah a little bit of setting the head up such as shimming the springs for proper height and youll be running that cam with ease.

 

With offset retainers and different springs you can run more lift on the stock heads, but that doesnt address the flow issues. With stock heads, the lack of flow will clamp the power band to around 4500 RPM. Not what you want. With offset retainers on a set of vortecs, you can run more lift with minor machining. IIRC, with stock vortecs, the max lift before interference was something like .520 on the intake and .550 on the exhaust with offset retainers. Or, you can just buy some aftermarket heads.

 

Even if you could get a set of springs to take the lift you will certainly risk pulling out the pressed in studs. You are going to need to replace them for screw in units. Flow issues aside, to run 187's and a cam past .480" lift you need to machine the valve guides and replace the pressed in studs.

 

Which brings you right back to the question of whether you want to put $400 inot a set of stock heads or just upgrade for afew hundred more.

 

its probly gonna be more like 100 bucks in machine work to have guide bosses ground down for clearance and setup for new seals. If he plans to keep a 1.25 spring that is. widen the pockets it will be abit more dollars.

he already has pinned in studs so no need for screw in stud work which is around 100-115 bucks last time i checked around here.

now if you add up springs/retainers/locks/shims needed to run that lift with 1.5 rockers, you get around 170 bucks or so, give or take. offset retainer OR locks with .050 shims will raise usuable lift to .530 or so. that should handle .510 exhaust on the exhaust side for sure.

 

you do not need locks with the spring/retainer combo i put up. for those 2 alone you can get them for under 200 easily. put those in with your ALREADY pinned studs and youre heads will handle the lift fine.

 

You have to also account for the fact that pretty much any junk yard head is going to need at least a valve job and maybe guides which get pretty expensive. I can have a set of heads ready to go for less than $250, but a lot of guys can't get under $500 for the same work, just depends on the going rate in your area.

Heads are THE most important part of your engine, if I had the choice between spending money on a set of heads and keeping the stock cam or buying a cam and moding the stock heads to handle the lift I would go with the heads everytime.

 

my guess is he already has the heads. if theyre low mileage you can work with them but if theyre high mileage you will need the machine shop like bmmontess said.