Mechanical cam with hydraulic lifters???

[65 Sting]

Guys, Some of you may have read my post a few days ago asking for info on A.I.R. on a 65 vette. After tearing the motor down for a rebuild, my engine builder found something weird. The cam installed in the HE 250HP block was casting number 3849347. I checked the code and found it was a GM 365HP Mechanical cam, but it had " hydraulic lifters"...:confused I doubled checked it and the cam code was correct. Question... Can that combo work? The car ran very rough before tear down, only 60lbs. average compression per cylinder!! The motor has been rebuilt and I pick the finished car up tomorrow, but that old combo has me puzzled. Any thoughts from John Z. or other vette gearheads?? Thanks for ant info. Steve

 

[ctjackster]

cool that the earlier efforts to L76-up your 250 base engine included the L76 carb, intake manifold, valve covers, and now even the cam, JohnZ can tell us if the hydr. lifters with this cam is a bad idea.

post up the exhaust manifold p/ns and try to measure the size of the exh pipe to see if they addressed the back side of the SHP equation too - one other thing, and I am sure JohnZ will mention this too - if you have a SHP carb, intake, cam, etc. the car won't run right until you put a properly set up SHP distrib on there - the vac can, for example, would need to be SHP spec or the car will NEVER idle right or perhaps stumble. look at the metal band on the distr. which MAY help to confirm proper set up (you should, if they really did the L76 thing, see a 1111069 p/n on the tag, but the distr. could have been set up for an L76 later on without doing anything about the tag), also look at the underside of the vac can for the number imprinted on the flange leading into the distr., which indicates the vac specs of the unit.

 

[JohnZ]

Just proves the old adage, "Bubba is everywhere" . Some backyard genius went to the trouble of installing the "30-30" cam and left the hydraulic lifters in it, which results in about .180" less lift at the valve (plunger travel x 1.5).

What cam/lifter combo did you use for the rebuild?

 

[65 Sting]

JohnZ and ctjackster, Since this vette is a local show and driver and not a NCRS, at least not now, I decided to install a Comp Cams 268H cam kit. I went with new stock rockers too. The 268H is 218 218 duration and a 454 lift. Less work than going to a REAL mechanical setup. I put a new stock crank and pistons in while I was at it. Car runs real nice now, just enough rump, rump to let people know it's not a 327 Impala motor. Ha! One other question though. My 4-speed Muncie shifter reverse lockout doesn't work. How can it be fixed? Or do I need to search out a replacement? By the way I had the orginial Holley and aluminum intake put back on with the finned valve covers. Only other change I did was to add a electronic ignition piece to the distributor and change the coil. Distributor DID NOT have a ID ban on it, guess it was removed at some point in the past. Since this is my first vette, I want to enjoy it the way it is for awhile. Later, as time and money allows, I will consider whether to go back to the 250HP stock look or not. Thanks for the help and any further info. Steve

 

[Tom65L76/96LT1]

Steve If and when you deciede to take your engine back to 250HP i think i have the #4457 intake manifold you need. It is left over along with some other parts from the restoration of my 65 and 66. Sitting boxed and on a storage shelf for the last 7-8 years,as i remember it was in VG condition,but i would have to take a look to be sure as i have not had it out in a very long time. If you have any interest or questions my email is Pologreen96vette@aol.com take care Tom in Apple Valley Minnesota

 

[6T5RUSH]

65 Sting:

With all that was attempted to make that 250 horse "go fast", you might find the answer to your reverse lockout not working due to an installed Hurst Competition Plus shifter and a "dummy" shifter handle that has the lockout spring tension, but is non-functional.