Timing on vintage 302 Z/28 A/S

[kirkwoodken]

If your car vibrates more than you think it should, you may have one of the driveshafts made with the yokes not lined up properly. Since the stock engine and rear ends are not mounted in the same planes, someone decided the solution was to offset the yolks. Lower rear gears made the vibrations much worse. Since I have no idea of what has been done to your car, thought I'd give you a heads up on this occurring. Thank Smokey for this info.

[Vintrcr]

Thanks all for the constructive comments and kind words!

Kirkwoodken, good tip! Fortunately she runs very smooth even with the 4.56 gears. We sure can thank Smokey for several things. He was very approachable when he was with us. The original owner had several conversations with him concerning the SY intake and setting up the carb correctly and kept good notes.

[pdq67]

Looking for advice on total timing for a vintage correct 68 Z/28. Stock bottom end. Standard bore, factory pistons. Jones solid flat 252/260 .544/.525 108L/C. Crower stainless 1.5. Smokey Ram , 830 Holley.
Heads are GM slant plug “492” #336746.
Should I expect best results with less total, say 34* with the slant plug heads?

I think that the, "vintage correct", cam should be the old -140 AND maybe the -754 so go from there OR call Mike and flat ask him where to baseline his cam in your engine combination!

Sorry, try this??


Chevrolet Factory Cam Specs with GM part numbers
Part # Lifter..duration @ .050 In/ex--Lift in/ex....centerline.....factory eng.

3849346 Mech - 254/254 - .484/.484 - 114 - 327 365HP& Z-28 302
3863151 Hyd. - 221/221--.447/.447-114 - 327-350HP, L79
3896929 Hyd. - 195/202 - .390/.410 - 112 - 327 300 HP
3896962 Hyd. - 222/222 - .450/.460 - 114 - 350 L-46, L-82
3927140 Mech - 257/269 - .493/.512 - 112 - Off Road
3965754 Mech - 262/273 - .488/.509 - 112 - 2nd design road race, short track
3972178 ?
3972182 Mech - 242/254 - .459/.485 - 116 - 70 LT1 360 & 370HP, 71 LT 330 HP
10134334 Roller - 235/235 - .480/.480 - 114 - 350ZZZ and ZZ2 Crate Motor
10185071 Roller - 208/221 - .474/.474 - 112 - 350 345, ZZ3&4 Crate Motor
10224241 Roller - - 92-94 GenII, LT1, 350
10243779 Roller - - 94-96 Gen II, L99 265 V-8
12353914 Hyd. - 180/194 - .378/.401 - - GM Crane Lo speed Hi torque
12353915 Hyd. - 194/204 - .401/.423 - 104 - GM Crane street
12353916 Hyd. - 204/214 - .423/.446 - 110 - GM Crane 305-350 street legal 50 states
12353917 Hyd. - 204/214 - .420/.441 - 112 - GM Crane nan-emissions vehicles & off road
12353918 Hyd. - 214/224 - .442/.465 - 112 - GM Crane marine & off road
12353923 Hyd. - 224/234 - .465/.448 - 114 - GM Crane off road
12364050 ?
12364051 ?
12364052 ?
12364053 ?
12364054 ?
12370845 Roller - 214/224 - .488/.509 - 112 - Off Road, lobe for mech fuel pump
12370846 Roller - 222/230 - .509/.528 - 112 - Off Road, lobe for mech fuel pump
12370847 Roller - 232/242 - .539/.558 - 112 - Off Road, lobe for mech fuel pump
12551142 Roller - 203/210 - .476/.480 - 115.5 - 96 350 LT4 w1.6 roller rockers
12551705 Roller - 201/208 - .447/.459 - 112 - 95-96 Gen II, LT1, w center dowel pin
14088843 Hyd. - 202/206 - .403/.415 - 115 - 305 HO, 83-86
14093643 Roller - 202/206 - .403/.415 - 115 - 87 350 Corvette, IROC Camaro
24502476 Hyd. - 121/220 - .435/.460 - 112.5 - 350 300 crate motor
24502586 Roller - 218/228 - .525/.525 - - 96 LT4 H.O.T. crate motor, use with 1.6 roller rockers
NA........ Roller - 202/210 - .472/.478 - 111 - 97 Gen III LS1 Corvette 350 uses 1.7 roller rockers

As always, just trying to help...

Back years ago on Team Camaro, there was a guy that raced 1st Gen. 302's and such. I forget his handle or his name but I think that it was either Gene or Dave??

Anyway, he flat knew his shit from doing it.

You might want to look him up and talk to him.... if you want to take the time..

pdq67