[Dragncar]

I have always thought of the 67 non drilled 2 bolt 400 block as a very beefy block. Well they are. Thick cylinder bores I am told and you can see the lifter bore area is nice and thick(dirty block is 67) This one is already .060 over with water damage in the bores so it will need to have thick bores if I am to ever use it.
The 73 block looks like most any other in the lifter bore area.
But look under the main caps how beefy this 73 non drilled block is. Its just about as thick as the splayed cap and does not get smaller under it. Like a 455 block there. But the 67 2 bolt does get smaller under the cap, less iron.
I guess I would rather have the 73s thicker thicker main bulkheads vs the 67 thick lifter bores and thinner main bulkheads.
The billet cap block is getting a 100% Megga Brace anyway.
What is considered the beast all around 400 block short of a RAV ?
The 73 seems like a nice block. Maybe Dan knew something. He sold it to me. It had been sitting under his bench for many years.
Sorry, 67 main area pic is a little blurry, but you can see what you need to.

[Dragncar]

This is how much thicker the 67s lifter bores are. The caliper was set on the 67 and put over the same lifter bore on the 73.
Its just over .040 difference. Quite a bit really.

[steve25]

If your running a 3. 750" Crank even at the 700 hp level I don't see the thinner web's being a issue .
It's a matter of rpm loads/,stroke and the indexing of the Crank counter weights along with proper balance that make for the amount of Bearing loads seen that then get transferred into the block.

A 4.210 stroke loads everything up 10% more at any given rpm then a 3.750" stroke Crank for example, and yes you can lighten up the recipercating loads by 10% to even things out pretty easy by going to Aluminum Rods, but you can't change a big stroke Crank from trying to drive the piston through the bottom of each Bore on the way up and the secondary loading that makes on the main web area of the block.

[Half-Inch Stud]

Surely the Small Journal blocks have such variety.

My experiences with the large Journal Blocks indicate a yearly tweak (for worse or better) from 66-73. I favor the Thick Main Webs. (Also favor the 2-Bolt block, undrilled for 4-Bolt).

Have had plenty of 4-Bolt 428s, and the drilled 455s to prefer the Thicker Main Web.

[73 TRANSAM]

I also noticed this as I used to have a 67 block and had the 73 400 block. It is clear that the 73 had more meat in the main webbing than a 67. This is both with only 2 bolt holes drill in the block.

[straycat]

Been looking for a good 400 block and came across a std bore 65-389. How does it compare to the 400s?

[ponjohn]

Why not stud the outside holes?

[chiefbigb]

I have sonic tested probably 12 blocks of all years. They are all over the place. Lifter areas the same. Find one that is usable and move forward.

[Richie Hoffman]

just sonic checked 3 67 400 blocks we’re all over the place and thin at .060

[mysticmissle]

but i heard on the intrawebs they are the best lol. so much bs out there.

[Half-Inch Stud]

Originally Posted by ponjohn

Why not stud the outside holes?

My opinion is the Outside Main Cap Studs, Bolts, holes do nothing, nada, no good.


Would you run a motor with Outer Studs, and no Inner Fasteners? no.

[PAUL K]

67 block is a major disappointment, IMO

[Dragncar]

I took a couple pics of the 67 with a different camera. Yeah, I was kinda disappointed in the 67 myself. The vaunted Marty P block that made 1400+ HP back in the day. Looks beefy on the top side but then you turn it over........

Is the sonic checking equipment expensive ? How much do shops generally charge to do it ?
I have a 71 block that has the un threaded outer holes. .030 over. Maybe I will dig it out and see how that main bulkhead area compares to the others. Its in rough shape. Deck has some large rust pits in gasket hole spots where plain water sat for a long time. 2 holes might need sleeved but 400 blocks are getting harder to find these days.
If the 67 sonic checks OK for a past .060 overbore it will just get a 400 crank. Fat bore 400 might be fun. Try to get the nephew to get a Pontiac in his dads 84 Bird drag car.

[Bill Eveland]

My uncles friend with a dragster has a 73 400 block .150 over and still good.

[Dragncar]

Originally Posted by Bill Eveland

My uncles friend with a dragster has a 73 400 block .150 over and still good.

Cool Bill, thats nice to know. I would only spend the money on billet caps and machine work if I started out with a std bore one. Good thing Dan just had mine laying under his bench. 200$, got a more than fair deal.
BTW, found that spacer I got from you. Looks a lot like the one Wilcox made out of wood.

[mgarblik]

Originally Posted by Dragncar

I took a couple pics of the 67 with a different camera. Yeah, I was kinda disappointed in the 67 myself. The vaunted Marty P block that made 1400+ HP back in the day. Looks beefy on the top side but then you turn it over........

Is the sonic checking equipment expensive ? How much do shops generally charge to do it ?
I have a 71 block that has the un threaded outer holes. .030 over. Maybe I will dig it out and see how that main bulkhead area compares to the others. Its in rough shape. Deck has some large rust pits in gasket hole spots where plain water sat for a long time. 2 holes might need sleeved but 400 blocks are getting harder to find these days.
If the 67 sonic checks OK for a past .060 overbore it will just get a 400 crank. Fat bore 400 might be fun. Try to get the nephew to get a Pontiac in his dads 84 Bird drag car.

Hand held sonic testers are available from various manufacturers. Dakota Instruments is probably one of the most popular brands for automotive engine blocks. You need the basic unit and then a number of different shaped transducers to get good readings on flat and cylindrical objects. A mid grade Dakota unit with 4 transducers is right at 2K. A shop willing to do a thorough job on all the cylinder barrels and webs, outer walls will charge around $100.00 here in OH.

[charlie66]

Originally Posted by straycat

Been looking for a good 400 block and came across a std bore 65-389. How does it compare to the 400s?

I weighed my 65 389 and a 73 400 on the same scale and there was a 25lbs difference. The 73 was heavier.. So i used the 73..

[Dragncar]

Originally Posted by mgarblik

Hand held sonic testers are available from various manufacturers. Dakota Instruments is probably one of the most popular brands for automotive engine blocks. You need the basic unit and then a number of different shaped transducers to get good readings on flat and cylindrical objects. A mid grade Dakota unit with 4 transducers is right at 2K. A shop willing to do a thorough job on all the cylinder barrels and webs, outer walls will charge around $100.00 here in OH.

Thanks, 100$ is worth it. I wish there was some cheap Harbor Freight unit for 300$ the average guy could have in his garage.

[Bruce Meyer]

Originally Posted by charlie66

I weighed my 65 389 and a 73 400 on the same scale and there was a 25lbs difference. The 73 was heavier.. So i used the 73..

I can believe that. I had a 65 389 block laying around. On day I took a closer look at it and all I could think of was its wimpy. Very thin lifter bores. I sold it for 40 bucks just to get it out of my way.

[Fast 69]

I just recently sonic checked my 67' .030" over 400 block. The thinnest spot I found was the front side of the front 2 cylinders. The spot you can see thru the water pump holes. It was .150"-.160. The rest of the cylinders averaged between .240"-.300". I was surprised they were that thick. And yes, I recalibrated my meter and double checked. Lol