Big block questions.....
 

What do these numbers on the front of the block represent, T02090 THB? It's a 72 402 based of the casting numbers on the rear of the block. I'm pretty sure the first T is for Truck, but I'm not sure what the rest of the numbers stand for (VIN#'s ???).

Also, it's got a cast iron intake on it that has "HOLLEY" embosed on it. Anyone know anything about this? WIW?

Re: Big block questions.....
 

The prefix portion of the ID code tells you the assembly plant code, and the engine's production date (for example, 0701 = July 1st....no year is indicated).

T 02090

Looks like the first T = Tonawanda and the rest 02090 is the date 02/09/70 would be my guess, but it is a 72 model so not sure. The block should have a date code cast into it as well. But by the three letter code it is a 402 from a truck.

The suffix portion tells you the original model year / engine / transmission / car combination when it went down the assembly line (for example, CTY = 1970 396 Camaro, 375 hp, 11.0:1, TH400).

THB 1972 Truck 402 210 400 L-47 30, fwd




As for the holley cast intake, I'd love to see the intake, I was not aware Holley made a cast iron intake, but they could have. As for value? Is it a running driving motor? If it is and everything is A-OK somewhere between $300-800 (remember gas is $/gal) and a 396/402 isn't as popular as the 454's. Just my opinion. If it was a 396 out of a Chevelle or camaro and had the 3 let code to verify, it might be worth more?

Re: Big block questions.....
 

The numbers on the block are confusing and inconsistent. It definitely is a cast iron holley intake. I found some info that mentioned that it was on a 427. I'll pull the casting numbers later. Thanks for the info.

Re: Big block questions.....
 

The intake looks like mine. It is a GM (Holley) cast Iron.

Re: Big block questions.....
 

The casting numbers from the back of the block were used and reused (so several motors could have the same casting number), but, the stamped numbers are for that block and only that block (more reliable than the casting number, IMO). As far as the date code in the T02090 series, I am not positive about the number being the date or if it is part of the VIN as the quote I attached says it is a date, but 02/09/ 0? if it is 70, and it could be. Then the motor was cast in 72 but then stamped in 70 (not likely) I think the numbers are part of the date and the extra 0 is nothing maybe, or it is the VIN, what are the last few numbers of the VIN?? As for the intake, it could be a GM/Holley collaboration for a Perf BBC. I have seen High rise BBC cast manifolds on Chevelle motors and such, just didn't know holley helped?? A casting number off the intake will help to ID what it came on if a GM number, may be worth some coin if it off of a muscle type high HP 427 like a vette?

Re: Big block questions.....
 

They worth a little money, but nothing like rectangular port high HP intakes. The cast iron intakes were made for mid-level performance, usually topping out around 350HP.

Re: Big block questions.....
 

That looks like it.

How much is it worth??

Re: Big block questions.....
 

Theu used to sell for a couple hundred all day long, but the market is off right now, so its hard to say.

Re: Big block questions.....
 

Thanks. This site breaks the TBH down....

Code Year Model CID HP Trans Comment
TBH 1970 Truck 402 310 L-47 10, 20, 30


http://www.nastyz28.com/gm-chevy-cod...-suffix-15.php

Re: Big block questions.....
 

Yep, but in your first post you put T02090 THB, cause I used the nasty z site to get that, so which is it THB or TBH?! TBH makes more sense since the date code stamped at the front says 02/09/0 (70 I assume) so with the numbers in the correct order it makes sense now!

Re: Big block questions.....
 

I'm starting to see double, I'm going to check it again.:uhmk:

Re: Big block questions.....
 

So how much HP would a 402 have?

Re: Big block questions.....
 

A '70 402 is rated at 310HP and 400 ft lbs of torque. '71 is rated 300HP and 400 ft lbs. '72 is rated 240 HP and 345 ft lbs with net HP ratings (dyno'd as installed, with belts, accessories, etc.) as opposed to the gross HP ratings that were used up until 1971.

Re: Big block questions.....
 

Wow I thought the 72 had more HP I might have to second think my project.

Re: Big block questions.....
 

Keep in mind that the '71 and '72 engines are almost identical, its just that the way they calculated the numbers changed.

Re: Big block questions.....
 

I've seen some tests done back in the day on a 70 Z28, 71 Z28, and a 72 Z28. Now obviously not apples to apples, but the 70 was rated 300hp, the 71 26 ish hp, and the 72 240hp, but in a race the 72 outran the 70 (testing was done in each new model year by Hot Rod or one of the mags) they took the times from each year and did a simulater race. The reason I point this out is that yeas the hp rating went down, but GM went from gross (on a dyno with no accessories) to net (tested as installed with all accessories) and the difference in compression went down over the 3 years and that seemed to help the later motor get more useable power and is OK with cheap gas of today! If I was going to build a motor, it doesn't matter what year it came from or the factory numbers as I will replace the pieces in order to improve perf. If I was buying a bone stock original motor to use as is, the 70 may appear appealing, but it would also have 98cc heads and a pop-up piston for about 10-11:1 compression and would rather premium fuel over 87 octane. For every benefit, there is a price to pay, high HP means high compression which then requires premium fuel, the price you pay to go fast!

Re: Big block questions.....
 

I checked it again and THB is correct although It doesn't match the 02090 code. Here's some pictures of the Holley intake:

Re: Big block questions.....
 

Bringing this back up. On the back of the block on the drivers side it says:

HI PERF
PASS
11

and there's a big K

anyone know what this means?

Re: Big block questions.....
 

I can't see from the pics but I am curious is that a dual plane intake or set up for direct q-jet bolt on.

It looks a lot better than my stock 72 intake with small runners.

thanks.

Re: Big block questions.....
 

It's a dual plane Holley intake. Quadrajet will bolt up. I've got a 750 dual feed holley also if you are interested. Are you interested in the aluminum valve covers too?

R/

Re: Big block questions.....
 

Based on the date of your intake I'd say it's for an engine for the 66 model year. Is there a boss on drivers side top near water neck with 1/2" pipe thread for a temperature sender?

Re: Big block questions.....
 

That's correct.

Re: Big block questions.....
 

So even though this intake is off a 66 its a direct bolt on for a 72 402?

Re: Big block questions.....
 

Yes, it would be a direct bolt on but there are differences under the manifold under the carb. I don't know what the differences do. The temperature boss is a sure way to tell the diffeence between 66 and 67 from the 68 and later ones. That intake is probably for a 66 Chevelle. The cast number 3883948 and cast date lean towards this. As for the engine, it would be interesting to see what the cast date is under the starter.

Re: Big block questions.....
 

I can't remember exactly, but all the block #'s pointed to 72.

Does the HI PERF PASS mean anything?