Factory small block 400 in 67 to 72?

[SCOTI]

Originally Posted by Rich69shortfleet

A SB400 built with 350 rods is a pretty solid engine, performance or otherwise. I've had a SB400 in my 69 since way back when, it came out of a 76 Blazer. I only wish when I built it ages ago I had gone with bigger heads and a bit more cam. I really wanted it to be a torque monster for towing and it does great, but it could have been better with better air flow. As it sits, it is pretty much done by 4500 RPMs. It came to me with a Q-Jet but I added an old fashioned Edelbrock Q-Jet Performer intake which did wake it up a bit. Glad I went with the 350 rods though, the 400 rods are kind of weak.

What cam did you use? The issue I've learned about was stock GM 350/5.7" rod hardware swinging on a 3.75 stroke crank comes much closer to the cam/cam lobes.

383's got really popular once 'rotating kits' came about as they helped w/the clearance issues by reshaping rod ends & using strategic hardware. I never knew clearance was a concern until looking into info on a cam.

[68Gold/white]

Originally Posted by Rich69shortfleet

A SB400 built with 350 rods is a pretty solid engine, performance or otherwise. I've had a SB400 in my 69 since way back when, it came out of a 76 Blazer. I only wish when I built it ages ago I had gone with bigger heads and a bit more cam. I really wanted it to be a torque monster for towing and it does great, but it could have been better with better air flow. As it sits, it is pretty much done by 4500 RPMs. It came to me with a Q-Jet but I added an old fashioned Edelbrock Q-Jet Performer intake which did wake it up a bit. Glad I went with the 350 rods though, the 400 rods are kind of weak.

A good friend of mine had a 66 C10 pickup, he'd had it since 1970. In the early 80s's he had a racer/engine builder in the smallish town(S.E. Oklahoma) we both lived in build him a SBC 400 for his pickup. At the time I was having the 283 built for my 67 Bel Air (my first car, I drove it until 1997, most of the time).

The engine builder is no one anyone here has heard of, his knowledge and skills were/are incredible! (he's semi retired now).

It was pretty simple, similar to yours.
He used the stock short rods with forged stock replacement pistons. The Comp 268H cam, not the XE version, which was years away back then, thankfully (The XE cams they sell have a very limited usage).
The only Edelbrock Performer available back then was the first design with larger runners (compared to the one they've been selling around the later 80's. The early version of this intake is likely better for a 400 cube engine). A Holley 3310 carb. 1-1/2 inch primary tube headers.

The heads were the common Chevrolet 441 castings with 1.94/150 valves. Of course the heads got some massaging before installation. I got to see them without the valves installed. They looked like they had hardly been touched? I asked the builder if they were done, he said yes...and that many folks grind too much and make them worse than stock heads....
On his Super Flo dyno the .030 400 made 300 HP and 400 ft/lb torque. Those numbers sound pretty wimpy especially compared to what some magazines print.
He always had his dyno calibrated on the stingy side, used NET numbers, nothing embellished at all.
That 400 in his 66 C10 (Muncie M20, 3.42 gear, mind you it was a long bed, weighing likely 5-600 punds over stock) was bad, bad badass to drive He sold the pickup in the mid 90's. I didn't know at the time, or I'd of bought it. The pickup owner pass in Jan 2022, he was a good friend, owned a machine shop (not automotive, though) He showed me how to operate some of his machines, I owe him a lot.

But!!! I have a more pwerfull 400 built ny same guy sitting in my shop, waiting for me to install in my 67 C10 (2Wd, long bed, also), THAT WILL BE A DAY!!!

[71CHEVYSHORTBED402]

Originally Posted by mr48chev

More time, energy and patience tonight let me search the GM Heritage center archives and the first Small block 400 in a truck was in 1976https://www.gm.com/content/dam/company/no_search/heritage-archive-docs/vehicle-information-kits/chevrolet-trucks/1976-Chevrolet-Truck.pdf

scroll down to page 28.
I'm going by what the GM Heritage center archives say and not What wikipedia says I had a 77 1 ton 4x4 that I wish I still had that had a 400 small block in it and even worn out that engine had more power than a fresh ring, valve job and bearings 350 did.

Agree, these archives are solid. The internet is full of misinformation, including AI.

[71CHEVYSHORTBED402]

Originally Posted by 68Gold/white

A good friend of mine had a 66 C10 pickup, he'd had it since 1970. In the early 80s's he had a racer/engine builder in the smallish town(S.E. Oklahoma) we both lived in build him a SBC 400 for his pickup. At the time I was having the 283 built for my 67 Bel Air (my first car, I drove it until 1997, most of the time).

The engine builder is no one anyone here has heard of, his knowledge and skills were/are incredible! (he's semi retired now).

It was pretty simple, similar to yours.
He used the stock short rods with forged stock replacement pistons. The Comp 268H cam, not the XE version, which was years away back then, thankfully (The XE cams they sell have a very limited usage).
The only Edelbrock Performer available back then was the first design with larger runners (compared to the one they've been selling around the later 80's. The early version of this intake is likely better for a 400 cube engine). A Holley 3310 carb. 1-1/2 inch primary tube headers.

The heads were the common Chevrolet 441 castings with 1.94/150 valves. Of course the heads got some massaging before installation. I got to see them without the valves installed. They looked like they had hardly been touched? I asked the builder if they were done, he said yes...and that many folks grind too much and make them worse than stock heads....
On his Super Flo dyno the .030 400 made 300 HP and 400 ft/lb torque. Those numbers sound pretty wimpy especially compared to what some magazines print.
He always had his dyno calibrated on the stingy side, used NET numbers, nothing embellished at all.
That 400 in his 66 C10 (Muncie M20, 3.42 gear, mind you it was a long bed, weighing likely 5-600 punds over stock) was bad, bad badass to drive He sold the pickup in the mid 90's. I didn't know at the time, or I'd of bought it. The pickup owner pass in Jan 2022, he was a good friend, owned a machine shop (not automotive, though) He showed me how to operate some of his machines, I owe him a lot.

But!!! I have a more pwerfull 400 built ny same guy sitting in my shop, waiting for me to install in my 67 C10 (2Wd, long bed, also), THAT WILL BE A DAY!!!

Oh man, what are you waiting for Kidding, takes a while, but that will be a day for sure. Change the oil every few 100 miles

That's true for heads, though I've never built an engine. I'm 2nd owner on my 71 c10, and right at 99-102K miles the engine died. The guy who rebuilt it was very reputable, I was lucky to catch him before meth did, he's long gone now. Anyway he said my heads had already been hit once, interesting. But he had a pair for the same fit and appearance, so, okay. He installed 1967 HP 396/427 heads, I can't complain much. He threw a high RPM cam in it, she's just a cruiser I threw a 67 Vette Antenna assm. at her too, by coincidnk, it's primarily 71 factory though. High crown with fixed mast, I like the parts best.

[Rich69shortfleet]

Originally Posted by SCOTI

What cam did you use? The issue I've learned about was stock GM 350/5.7" rod hardware swinging on a 3.75 stroke crank comes much closer to the cam/cam lobes.

383's got really popular once 'rotating kits' came about as they helped w/the clearance issues by reshaping rod ends & using strategic hardware. I never knew clearance was a concern until looking into info on a cam.

I don't recall the exact specs, I have the cam card around somewhere, but it is a flat tappet Crower Baja Beast cam. Good idle and low end torque, just gives up pretty early especially given the displacement. We had to bore it .040 over so it bigger yet than stock.

The heads IIRC have tiny valves, something like 1.76 intakes. The cam might even do better with heads that could actually breathe. The intake manifold is capable of a lot more flow than the heads can use.

[70STOVEBOLT]

Originally Posted by 68Gold/white

A good friend of mine had a 66 C10 pickup, he'd had it since 1970. In the early 80s's he had a racer/engine builder in the smallish town(S.E. Oklahoma) we both lived in build him a SBC 400 for his pickup. At the time I was having the 283 built for my 67 Bel Air (my first car, I drove it until 1997, most of the time).

The engine builder is no one anyone here has heard of, his knowledge and skills were/are incredible! (he's semi retired now).

It was pretty simple, similar to yours.
He used the stock short rods with forged stock replacement pistons. The Comp 268H cam, not the XE version, which was years away back then, thankfully (The XE cams they sell have a very limited usage).
The only Edelbrock Performer available back then was the first design with larger runners (compared to the one they've been selling around the later 80's. The early version of this intake is likely better for a 400 cube engine). A Holley 3310 carb. 1-1/2 inch primary tube headers.

The heads were the common Chevrolet 441 castings with 1.94/150 valves. Of course the heads got some massaging before installation. I got to see them without the valves installed. They looked like they had hardly been touched? I asked the builder if they were done, he said yes...and that many folks grind too much and make them worse than stock heads....
On his Super Flo dyno the .030 400 made 300 HP and 400 ft/lb torque. Those numbers sound pretty wimpy especially compared to what some magazines print.
He always had his dyno calibrated on the stingy side, used NET numbers, nothing embellished at all.
That 400 in his 66 C10 (Muncie M20, 3.42 gear, mind you it was a long bed, weighing likely 5-600 punds over stock) was bad, bad badass to drive He sold the pickup in the mid 90's. I didn't know at the time, or I'd of bought it. The pickup owner pass in Jan 2022, he was a good friend, owned a machine shop (not automotive, though) He showed me how to operate some of his machines, I owe him a lot.

But!!! I have a more pwerfull 400 built ny same guy sitting in my shop, waiting for me to install in my 67 C10 (2Wd, long bed, also), THAT WILL BE A DAY!!!

SB400 heads left the factory with 1.96 intake valves and 1.60 exhaust valves.

[RichardJ]

Here is a good list of 1st gen SBC, ID numbers, years used and valve sizes.
There are some gen II, gen III and BBC on the list to confuse you.

Cylinder Head ID
https://outintheshop.com/faq/casting/heads.html

Not one SB 400 on this list shows a EX valve larger than 1.50" and that's with 1.94" IN, not 1.96.

You want 1.60 EX , then you're looking for 2.02 Camelback heads.

[mr48chev]

To add to what 71chevyshortbed402 said I finally got my new computer working and went year by year from 70 to 72 on the GM heritage center vehicle information kits that are the straight from the factory info.

A snoop over on Rock Auto for 71/72 lists the engines as 402. Young guy might not know that but it was common knowledge in 71/72 that the truck with the 400 flags was a 402 that I believe is a .030 over 396.

Back in the Mid 70's when the 400 small block came out they usually got snagged out of wrecked trucks before they ever got put out in the wrecking yard. Some guys didn't like them because of the Siamese block and steam ports in the heads but those extra 50 inches really work.

If you are going to swap 350 heads onto a 400 block you have to drill the steam ports in the heads A lot of guys found that out the hard way.

[mr48chev]

Going year by year on Rock Auto they don't show a 400 small block in a C 10 before 1976. Their info is usually pretty accurate.

[70STOVEBOLT]

I must have had too much to drink when I posted the valve sizes. The memory ain't what it used to be...

[mr48chev]

At my age I have learned that it is better to stop and look up the specs/info to make sure I have it right the first time. I spent a good part of an hour last checking year by year GM heritage center vehicle information kits https://www.gm.com/heritage/archive/...formation-kits for info on when the first small block 400 came in a truck along with cheating a bit and checking Rock Auto's I have this engine list by year. The memory part was from listening to a few guys I was around in Texas in the early 70's who had a fit because the emblems on their 402 powered 72 truck read 400.