It is hard to read but I think that it says 8888882 and right next to it k12
on the other side it has what appears to be 21 or 12 and there is a bunch of
number further down towards the firewall that I can't read.
Used parts suck sometimes.
Thanks for typing all that out. I hope it wasn't to much trouble?
So then going by what you wrote here for me. The 333882 is only for 350 and
up? It couldn't go on the 305, it has to be 350. When I compared the 2
heads together while it was off I had them side by side and nothing really
stuck out like the valves being different sizes so unless they are really
similar to the naked eye they should be the same.
305 and 350 heads are the same except for combustion chamber size. My
guess on the stud thread length may be the difference for head that
were on a engine with factory rolled lifters or not as chevy switch
them over to this style lifter some time ago the the lifter is
longer/taller than a flat bottomed hyd one.
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I checked the lifters off the new head and they are the same size as the old
ones the push rods seem to be the same size too. And I know that they were
on the lobes when I put the intake on. they seemed to fit the old engine but
not my dads.
Lifters rest in the lifter valley in the block, not the head.
Lifters are shared amongst 1st
Gen SBC's at .842" diameter.
1st Gen 350's generally have 76cc open chamber heads, 305's from the same
era used a dished piston and 58cc closed chamber heads with a very
restrictive exhaust port and smallish valves.
Pushrods are also shared at 7.8" length,
unless the block or heads have been decked.
Locate a set of similar heads to the ones you are replacing and be done with
I have found heads that are identical to the ones I'm taking off. Except the
threaded post that adjusts valve lash don't seem to be threaded down as far
as the old ones. As it turns out I don't know if I can set the rockers arms
tight onto the pushrods. I was wondering if it could be different heads
because of this little threaded post problem. I could just tap the post down
farther if I need to. I don't know the pitch for those but it should be easy
enough to figure out if I just get the big tap and die set from autoplace.
Oh, you're dealing with variations on the rocker stud.........it should be
fine in your case.
Unless the lifter(s) has collapsed you wont have to run the adjuster nut
down very far to achieve zero lash.
350 and 305 and 327 and 307 heads are relatively the same head except for
combustion size and valve size. If chamber size and valve match, run them.
Does not matter unless you go into vortec or roller heads. Also on engine
notorious for lower compressions, 307 and 305 you will find larger chambers,
which does not hurt with today's fuel.
Ok I have an update of what happened. I decided to see what would happen if
I tried to set the lash. I got the 1 piston to TDC and I turned the crank
over 90degrees and I started to set the lash. I got it down to the pushrod
and it got very tight. I was relieved too. I backed it off until there was a
little drag. I moved on to all of them and then I did it again to handle the
other valve on the intake stroke. I set them loose to kind tough drag. But I
didn't over tighten them so I didn't think that I would get any backfiring.
I then put the alternator, power steering and misc brackets back on and I
attempted to start it. I had to tighten the gas line but other then that it
was very smooth. It took some trouble to get it going and I notice it was
backfiring but I didn't set the timing so I advanced it a little and it
seemed to stop back firing. I couldn't get it to idle though. I think it
maybe the EGR? It sounded real smooth running although it wouldn't idle.
I was getting allot of smoke off the exhaust too. But it could be left over
stuff that is burning off. I didn't see the valve cover leaking and adding
anything new. I was so close to getting it back together tonight. I couldn't
figure out a few vacuum lines so I thought we should pick it up in the
I want to thank all of you again for helping adding the technical input that
Chilton's and Haynes don't bother with. Thanks.
The easiest way to set the lash is rotate the engine to TDC and adjust
available valves at zero lash...no drag...just zero lash, then rotate the
crank 90 degrees and do some more....another 90 and some more until after 2
complete revolutions of the crankshaft which equals 1 complete revolution of
once your sure you have set all the valves at zero lash then you can tighten
each rocker nut another 1/2 turn without having to rotate the engine over.
When it backfires it means that either the timing is retarded or the rockers
on the intake side are to tight........this is assuming of course that you
don't have a burnt, bent valve or stuck valve.
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