Long day

[tom warner]

All J heads are the same.

>GMCers
>
>Well, there has been another setback. Had the heads Magna-fluxed
>today and one of them has a crack into an exhaust seat. I know some
>of you will say they should have been checked before the plugs were
>welded in. Well, I wanted to do it after to see if there were any cracks
>because of the welds. I dont think the welding had anything to do with
>it because it is on an end cylinder. Now here is my question. Of course
>I have "J" heads. My problem is that I am now looking for one head. Are
>"J" heads all the same or is there some other number on them that I
>should be looking at?
>
>Take Care
>Arch 76 GB IL
>
>

 

[tom warner]

Arch I answered a little to fast. The J heads came in 80cc and 82cc
configurations.

Also depending how the crack goes can you install hardened seats and
eliminate the crack?

>GMCers
>
>Well, there has been another setback. Had the heads Magna-fluxed
>today and one of them has a crack into an exhaust seat. I know some
>of you will say they should have been checked before the plugs were
>welded in. Well, I wanted to do it after to see if there were any cracks
>because of the welds. I dont think the welding had anything to do with
>it because it is on an end cylinder. Now here is my question. Of course
>I have "J" heads. My problem is that I am now looking for one head. Are
>"J" heads all the same or is there some other number on them that I
>should be looking at?
>
>Take Care
>Arch 76 GB IL
>
>

 

[tom warner]

OK Arch maybe this will help? Mondello disagrees with other olds "experts"
on the cc of other year J heads. Here is his table from his reference book.

Mondello Oldsmobile V8 Engine Technical
Reference Manual

BIG BLOCK CYLINDER HEADS
Unleaded Chamber
Year Casting # Type mt. Valve Ex. Valve Fuel Engine Volume
1965 383821 3/8.' Rocker Stud A 2.070~300 1.625450 No 400425
80cci
1965 383821 318" Rocker Stud A 2.000450 1.625450 No 425-2BBL
80cci
1965 389395 Irrigation B 2.070~300 1.62545~ No 425
BOcci
1966 3893~95 B 2.000450 1.625450 No 425-2BBL
80cci
1966 38939~5 Drill Spot B 2.070~300 1.625450 No 4001425-4BBL 80cci
Th967 3945~4~8 Drill Spot C 2.070~300 ~5[4~50 No
400I4254BBL 80cci
Th967 39454~8~ C 2.000450 1.625450 No 425-2BBL 80cci
1968 3945~48~ C 2.000450 1.625450 No 455-2BBL 80cci
1968 3945~4~8~ C 2.070~300 1.62545~0~ No 4~554BBL 79cci
1968 400370 (W-30 2 Ribs @ End) 0 2.070-30~ Th62~54~50 No 45S4BBL 72cci
i969 394~548~__________________ C 2.000450 Th62~54~50 No 4~55-2BBL 80cci
~1969 39454~8__________________ C/CA 2.070~300 1.62545~ No 4~554BBL 79cci
~~1969 400370~ (W-30 2 Ribs @ End) DIDA 2.070~300 Th.62~5450 No
4554BBL 72cci
1970 403686~ E 2.000450 1.625450 No 455-2BBL
80cci
~1~~970 403686~ (W-33 & W-34) E 2.070~300 1.625450 No 4~554BBL
79cci
1~~970 404438 (W-30 2 Ribs @ End) F 2.070~300 1.62545~ No 4S54BBL 79cci
1~97~ 4091003 Ribs @ End G 2.000450 1.625450 Yes 455-2BBL 80cci
~1971 409100 G 2.000450 1.625450 Yes 455
80cci
1971 409160 (W-30 2 Ribs @ End) H 2.070~300 1.625450 Yes 455-4BBL 79cci
1972 409100 3 Ribs @ End G 2.000450 1.62545~ Yes 455-2BBL 80cci
1972 409100 3 Ribs @ End W-30 GA 2.070~300 1.625450 Yes 455
80cci
1972 409100 All Exc. Toro & W-30 GA 2.000450 1.687~300 Yes 455
80cci
1972-76 4~09100 GA 2.000450 1.625~300 Yes
455 80cci
1973 411783 J 2.000450 1.625450 Yes 455-2BBL
79cci
1973 413191 KA 2.070~300 1.625450 Yes 455
79cci
1974 411783 J 2.000450 1.625~300 Yes 455-2BBL
79cci
1974 4i3191 KA 2.000450 1.625~300 Yes 455
79cci
1975 4i~1783 J 2.00045~ 1.625~300 Yes 455-2BBL
79cci
1975 413191 KA 2.000450 1.625~300 Yes 455
79cci
1976 41~1783 J 2.000450 1.625450 Yes 455-2BBL
79cci
1976 4~13191 KA 2.070~300 1.62545~ Yes 455
79cc+
***Marine ~
1971 4Th~9100 3 Ribs @ End G 2.070~300 1.62545~ Yes 4S54BBL 79cci
1972 4Th~9100 (L-75 3 Ribs @ End) G 2.070~300 1.625450~ Yes 455-4BBL
80cci
1973-76 413191 Cutlass442-Marine K 2.070~300 1.625450 Yes 4SS4BBL 79cci

66
Casting ID Letter ~U';dLIUfl

 

[tom warner]

other than what mondello noted in his table, ie; all J heads measured the
same cc's, there are no differences that I can see.

>In a message dated 11/16/1999 10:30:35 PM Central Standard Time,

>
>> Arch I answered a little to fast. The J heads came in 80cc and 82cc
>> configurations.
>
>Yeah I was about to nail your butt to the wall from your first post but
>I was having fun in a chat room---then saw this post. Guess If I take
>them both down to 70cc it wont make much difference. Do you know
>of any other differences? Got any IDs on 80s or 82s---guess it wont
>make much difference-----but darn I seem to need to know.
>>
>> Also depending how the crack goes can you install hardened seats and
>> eliminate the crack?
>
>Sure wish I could---I am not going there---my problem
>
>Take Care
>Arch
>
>