Hi
I own a 68 convertible.
Unfortunately, it has a non original big block installed.
Everything points to a original L71 or L89 car.
I'm looking for a block casting 3916321.
Allan71 already told me that a casting date of H or I 67 would be ok.
Car's VIN is 194678S401391 build date Oct 05 , 67.
Since this blocks are not easy to find, what are the limit dates still acceptable, from to ? Suffix T.....IR or T....IU ?
Can I find a bare block for under 1.000 US$ ?
Does anybody possibly know of such a block for a reasonable price, not 1.500 or even over ?
Thanks a lot, Gunther :seeya

 

Gunther,

I am meandering down the same road you are. I would tend to lean more toward finding the correct dated block and not worry about the identification code. If you are looking for points, you will not suffer a points deduction if your date is correct, but will if your VIN does not match. If your VIN does not match it doesn't matter what the assembly stamping is b/c you will lose total points and not partial. Therefore, you open your opportunities to a correctly dated block, but it could be IL, IQ....heck, it could be a Chevelle 427 for all you care. If you are trying to match it for resale...I wouldn't think a correctly coded block would bring any value to the car, only headaches trying to find it.

As for finding them...they are out there, just keep looking. I will see a 'quality' one for sale every about two months or so. It seems the asking price for just block and crank/caps is $1500. Do be careful of 'engine or parts dealers' they seem to find a way of altering the date code to what you want. I would ask if they have a 427 dated Feb, March, or April of '68 and before I get the last syllable out, the answer is "YES".......????WTF??

Ask first what date code he has instead of what you're looking for and that will cut to the white creamy stuff pretty quickly. Also, don't say Corvette or the price goes up as well.

As for what date code.....I would think even a dated block earlier than that would be OK say by about two months...especially since they might have been hold-overs from '67. Good Luck.

BTW...I am looking for a A,B,C, or D block if you run across one. :seeya


[Modified by topless68, 2:37 PM 1/12/2002]

 

I guess the real question is, How close to body build date can the engine casting date be? Gunther has located a block with casting date I277 or Sep 27. His trim tag date is Oct 05. Possible? or is this too close?.

 

Quoted from the '68-'69 Technical Info Manual & Judging Guide:
The engine casting date must precede the engine assembly date, and both must precede the vehicle assembly date by no more than six months.

I would think this is acceptable, but my question is this:
While technically this is legit, is it realistically feasible for a block to be cast on Wed the 27th, assembled, and make it into the car by Thurs Oct 5th, one week and one day later. Under the assumption that the factory was having a very good week that week, it might be possible. In real world judging...I will defer to some of the more experienced memebers.

See if Chuck S. or Chuck Gongloff are hovering about and get their IMHO.
Good luck.
:seeya

 

My opinion is that, ideally, there is usually a little more time than a week between the engine build date and the car's build date, but maybe there is a case with only several days. The NCRS "Corvette Judging Reference Manual" indicates that the average normal production time span is about two to eight weeks. This agrees pretty closely with my own car; the engine was built 22 days before the car.

As a practical matter, however, how far can you take this? A replacement engine is a replacement engine, and even if its build date does precede the car build date by the average 2-8 weeks, what difference does it make? NCRS does not judge engine casting dates or asssembly dates as being too close to the build date to be reasonable, only that the casting dates precede the engine build date, and that the engine build date precedes the car build date by no more than six months.

From the NCRS' "Corvette Judging Reference Manual", the following sequence is followed in judging the cylinder case:

(A) Correct, normally configured casting number and case configuration. If incorrect, deduct 350 points and do not judge casting date or stamp pad.

(B) If (A) is correct, judge for correct, normally configured casting date within six months prior to car build date. If incorrect, deduct 175 points and do not judge stamp pad.

(C) If (A) and (B) are correct, judge for correct, normally configured engine plant stamp (assembly date, prefix code, suffix code). If any part of engine stamp is incorrect deduct 50 points. If engine has VIN derivative stamp, the 50 points may be divided between the two stamps, but pad must judge "OK" in (D) below.

(D) Judge for absence of paint, dirt, rust or other conditions which obscures pad. Judge for presence of normal production machining marks. If either is judged negatively, deduct 38 points.

The bottom line is if the engine is a replacement engine, you are pretty much going to lose a minimum of 50 raw points (total raw points around 2000). This assumes that you can find an engine with correct casting numbers and casting dates that precede the car build date by no more than six months. Fifty points is pretty good hit, but not as bad when you consider that an engine with incorrect casting numbers and incorrect casting dates will cost you 350 raw points.

 

On my original engine 73 Corvette the car's trim tag date is July 20, the engine stamped date is July 16 and the block casting date is July 9. They can move fast when they want to.
Roger

 

RMS, the proximity of your engine build date to the car build date demonstrates that it was possible to have only a few days separation. But the block cast date (July 9) and the engine build date (July 16) is pretty typical in my opinion. They didn't let that cast iron set around long before the engine was built. In fact, most of the casting dates on the engine will be pretty tightly grouped within several weeks before the build date.

I think Allan71 really asked the critical question above because of the engine build time. If you were looking for the most authentic block to RESTAMP, then the September 27 cast date would be right on the ragged edge for Gunther's October 5 car build date. In my opinion, to make it look authentic, you would have to stamp the "engine build date" allowing for about a week of engine build time, and allowing a few days before the car build date; say T1001XX or T1002XX. I think that would work. Of course, if you were smart, you would want to check a 1967 calender and make sure that your "engine build date" didn't fall on a weekend/"off" day. :D A block casting date any closer than September 27, and it would begin to look pretty suspicious.

As I said before, for NCRS judging purposes, all of this discussion is pretty academic; if the casting date precedes the car build date by no more than 6 months, he should be OK.


[Modified by Chuck Sangerhausen, 12:14 PM 1/14/2002]


[Modified by Chuck Sangerhausen, 12:23 PM 1/14/2002]

 

Total raw point allocation is 4500 - the block casting number and casting date carry the overwhelming potential point deductions (525), compared to only 50 for the engine plant stamp and the assembly plant VIN derivative together (plus 38 more if the longitudinal broach marks aren't there). Just depends how good the rest of the car is to determine if you can afford the potential deduction for the stamp pad data, assuming the casting number and date are OK.

 

Thanks a lot for the good info.
So I could go for this block, even that it is realy tight on the date.
The stamped suffix is T I03067 IR , so was in this case a complete month after the casting date of I 27 7 .
If I get it for a good price, I will take it.
Again, thanks for all info.
Gunther :seeya

 

The way I read the judging reference manual, if the block casting number is correct, NCRS judges would deduct 50 points for the stamp pads being incorrect. Assuming you don't have the block decked and lose the broach marks, that should be your total deduct. If you decked the block, then you would lose another 38 points.

If it were me, I would confirm this with the NCRS National Judging Chairman before investing a lot of money in this engine. Yours truly has been wrong before, and frankly, I wouldn't trust the guy when it comes to dropping $thousands$ for a replacement engine. :D :D

 

I looked I have 3914660 in one of my cars Sorry

 

Andy, 3914660 is the 68 small block casting number. Gunther is looking for a big block replacement; 3916321 is correct for an early 68 big block, and Gunther's is so early it was built in 67. :D

JohnZ, you are correct: the beginning total raw points used in NCRS judging is 4500. I thought I remembered 2000 or 2100 from the judging sheets when I last judged, but the number is right there in the Judging Reference Manual. Alas, my initials, "CRS", are becoming more appropriate with each passing year. :cry