I need a little advice. Have my engine out to sort out a ring (light oil burning) issue. During this exercise I have documented all the numbers and castings of various parts. So far things all look in order for a numbers matching situation with one exception, the heads have a casting date 5 months after the assembly date for the car.I assume that at some point the heads were replaced. They are a matching pair. Since the car is fairly original should I start looking for a better matched casting date. How far ahead of the car assembly date or engine casting date could the heads be for a true original build?

Trim Tag f22 F=Jan 69, 22= 22nd day

Engine Block
Punched number matches body VIN
engine block casting number 3956618, 350 CUBIC INCH, 300 HP, 350HP
V0111HW
V Flint Michigan
0111 11 January
HW 350/350 with manual transmission (no A/C)

Head 1 and 2 casting no 3927186, 350 CUBIC INCH, 300HP, 350HP, (Correct for Car)
G249
G July
249 24th 1969

Exh Manifold right 3932461 correct for car
Exh Manifold Left 3872765 correct for car
Intake Manifold Castign Number 3927184 correct for car

Muncie gearbox
main body casting number Correct for car Casting: 3925660 Years: 1968 - 1970 Ratios: M20 2.52 1st , M21 2.20 1st, M22 2.20 1st
main body punched matches engine/vin
main body punched P9A13A p=Muncie Plant
9=1969
A=January
13=13th
Letter: A M20 Ratio

Rear Diff Punched 1AM12 16 68W AM = Posi 3.36:1 AM
121668 (December 16th 1968)
W = Warren Michigan

Engine is bored 30 over, looks like it had an issue with ring gaps and wear in top ring. Cylinders and pistons and hone is good, etc. Is it worth my time, since the rest of the setup is fairly original, to find new heads and what date should I aim for for the castings, Dec 68, Nov 68?

 

The NCRS does not judge head casting dates. While your pair are not original, they are correct. Why not keep what you have?

Dates can vary as long as all dates precede the engine assembly date. Dates do not have to match. I have one original head dated the end of March and the second dated the beginning of April. Both dates are before my engine assembly date of April 9th.

Do you have a copy of the NCRS Technical Information and Judging Guide?

 

I agree with Mike, if good leave alone. I had to find at least 1 head for my early 69' as it had cracks in the water jacket. I ended up buying a matched pair. I would guess within 30 days prior to engine date would be a good time frame. I also guess you will invest over $1000 for the heads and to have the valves done. Now you could recoup a good portion of that by selling yours, but to what end?
Joe

 

Thanks for the replies and perspective. I will probably look into buying the NCRS book for 1969 soon ($55 hmmm, some other years are $34) so at least I will be more informed and can judge the true condition of my car. If I locate a pair of heads in decent condition without breaking the bank I'll grab them but I won't go overboard trying to find a match.

 

Hi Garry,
While it's true that the NCRS doesn't check the casting number and date as part of Flight Judging it might still be nice to look for a pair of heads on which the dates 'work' with your engine's assembly date.
It's something that not everyone is going to care about but a few people will. Do you?
For some people the 'numbers matching' quest extends FAR beyond the commonly considered engine stamp pad and body VIN tag. For them the information in the 68-69 TIM&JG is a goldmine.
The 68-69 Technical Information Manual & Judging Guide is a relatively new edition (4th Edition, 2012) and includes quite a lot of information that the earlier manuals didn't. This is because the body of knowledge continues to increase dramatically because of the number of cars being seen and the number of members involved with judging and the production of the manual. It also now includes some interesting 68-69 Service Technical Bulletins and excerpts from the Chevrolet Service News that apply to 68-69 cars. I think you'll find it WELL worth the price if you're interested in 68-69 cars in detail.
Good Luck!
Regards,
Alan

 

http://www.ncrs.org/

 

The reason why nobody judges the casting dates is because the Valve Covers need to be removed to see them. Removing a Breather might reveal them but disassembly to check correctness is not going to happen at a car show. If it was OK, then we would be pulling Oil Pans to check the Crank and Rods. The line has been drawn at no disassembly.

 

My block is V0108HX, I need to check the trim tag, hard to get to now, I recall F20. My vin # 9S713758 interesting time frame!

 

 

My opinion for what it is worth - If the engine needs to come apart to fix something AND you could find a closer match dates now, I would do it. Within the preceding 6 months is good.

Finding the right dates for your components can be an enjoyable "hobby" all by itself. If you love the "score", do it. The value of the car is not significantly altered either way based on head dates alone.