What to look for in used 400 block
 

This Saturday I will be checking out a used 400 SBC as a possible candidate to replace my recently lost 383.

It is a 2 bolt 400, already bored .030 over. Casting number 3951509 (383). Seller includes Enginetech pistons.

Any pointers what to check / inspect / look for?

AKAIK, enginetech is one of the cheapest, rebuilder-grade pistons and I've never heard of a forged enginetech.

Check bore size closely, it may be bored to +0.030" but is it worn so that it needs boring again to suit your needs?

Look for cracks on the deck as well as down in the mains webbing. Find out if it was tested for cylinder wall thickness. Some of the blocks had a lot of core shift and so have thin cylinder wall in spots. Has it been decked and line honed? If not, I would get that done.

Mike

Is there a shop you can take it to to get it magnafluxed and mic'ed? You can not use your 383 crank. At least not without .200 spacers, which are not recommended. You can't go much bigger than 30 on a 400 block. And you want forged pistons after your last episode.

This is probably way overkill and probably destroys the budget, but I had to post it.

This 427 SBC is for sale in Hayden, Idaho.

Dart SHP Block, AFR 220 heads, 4 bolt splayed mains, ARP everything forged H beam rods, SFI certed flex plate, canteen road race oil pan, RHS port EFI intake, 24 lbs bosch injectors, Kingler 1000cc EFI TB, MSD ignition box with external coils, custom lingenfelter valve covers, Comp roller cam, 10.9:1 CR.

He's sold off the pulleys and water pump about a week ago he dropped the price to $5,200 (not reflected on the FB page.) Or $4k just for the DART 427 SHP short block and canton road race pan.

https://www.facebook.com/marketplace...32611713560836

It's just an incrediblly nice build, I can't believe the guy abandoned it for a 615 BBC. -He claims to have $14k in receipts.


Adam

P.S. He REALLY Wants to sell it to someone with a 3rd gen and keeps dropping the price on a 3rd Gen FB page, but not for the general FB Marketplace ad....

that's a great deal for someone.

FYI... that's KINSLER INJECTION not with a g.

400 blocks are inconsistent but many won't handle more than 0.030" overbore. I read often you guys overseas get ripped off because of scarce american parts and trusting unscrupless/dishonest advertisers here stateside. I bought three 400 blocks here in Las Vegas all 2 bolt standard bore - but they become available infrequently. We found a nice 4 bolt 400 short block for a friend only like 30 miles from his home but he was very patient and waited for just what he wanted.

Now a bare block sbc weights less than 200lbs and many don't realize they can ship it freight with the airline. I knew someone that would travel Europe with his motorcycle and had it shipped as freight with him. But it may take a lot of planning to get it to the airport let alone locate a good 400 block to purchase.

My advice is be patient and wait for a good standard bore block. Standard procedure for inspecting any block is magnaflux for cracks.

Good luck.

Just an FYI save your pennies and buy a new Dart shp block

:iagree: A quick look at eBay tells me guys are looking to get $7-800 for a 400 block. That's an unknown quantity and you are looking at substantial machine work. For about $1700 you can get a Dart block. Its a better piece, you know what you are getting, and it won't need as much machine work.

Just so you can have a comparison price. 4 summers ago I purchased a 400 4-bolt block from a local machine for $200. I trust him as he is also a neighbor and has an excellent reputation among the circle track racers. The block needed to be bored to .040 but was magna fluxed before and after. It now has 25,000 miles. So keep looking until you find a good buy. Maybe a good place to search is all of the smaller engine builders here in the states. There are thousands of them. T

Thanks all! I'll take a lot of pictures and consult my engine builder with those.

Look for a forged 350 crank and a Dart 400 block and make a high-revving 377, like this:

CNC 377

Just a suggestion, but why go with an early SBC ('68 to '86), when you can get a '87-'91 Factory Roller Cam block? The roller cam blocks can run cams with a faster lift profile, as well as more lift than their older brethren and with roller lifters, you save yourself the flat tappet cam hassle of having to break in the cam (or have it wiped on start up). A lot of people are 'retrofitting' older blocks to run a roller cam, but it's twice the cost and there's the nylon cam button and expensive two piece timing cover that you have to run.

Edit, mine was a four bolt main to boot. Unlike my bare block, the engine below comes with all the accessories, like the lifter retainer and it's hardware, dog bones (prevents the roller lifters from turning), the cam thrust plate, along with two torx bolts (for clearing the timing chain, no nylon button needed) and the rear main seal housing and hardware for the one piece rear crank. This will take any SBC head and is exactly the same fit as any other 350.

https://cimg5.ibsrv.net/gimg/www.cor...b9355d70df.jpg

I searched the interwebs (including this forum) and a 406 in general seemed to be considered a good build route. I can reuse the parts left from.the 383 and sell what I don't need (pistons...). Perhaps not even purchase those.

Roller blocks here, are about as scarce as 400 blocks and this one can be had for a reasonable price.

However; I'm just having a look, so no worries :)

Find someone who sells used C4 Corvette parts on Craigslist, that's who this guy is.

Some good suggestions about options.

Just my 2 cents on retro Roller cams for the Gen 1 SBC after installing a howards roller cam in my SBC Gen 1 355 78 L-82 back almost 5 years now. Most of the hype about the difficulty using a retro roller cam in a Gen 1 SBC is complete nonsense and don't be afraid of doing one if you decide. Most of the steps are very easy and do not require any special treatment..I mean that. The most careful step is measuring for the new pushrods with the roller cam and even that step is completely blown out of proportion, so much so, that after doing that step, I really wonder what is behind some of the scare tactics.

Case in point, with a howards roller cam there is no need for a special distributor gear OR fuel pump pushrod. I used my OEM stock units for both and 5 years in zero issues after speaking directly with Howards.
# 2. With a double roller timing chain and the nylon button, I simply slightly dimpled the OEM timing cover to incorporate the nylon cam button. No trail and error and no removing and installing the timing chain cover-My builder's trick that he has used forever who did my engine's bottom end only. No drama and zero issues.
Myth #3: You need to change to an aftermarket timing cover since the OEM one will flex under the load of the cam trying to move forward and the pressure from the cam button. NOPE, not in a C3 corvette SBC in which the OEM timing chain cover is very strong AND the timing cover sits directly against the back of the water pump. Impossible for the cover to flex AND no way the roller cam is walking forward with a double roller quality timing chain and the cover wedged against the water pump

I can go on but the message is a retro roller is really not difficult.......Just for the record........

A SBC is not a Ferrari engine or even a mercedes AMG motor...These motors are VERY forgiving and fairly indestructible with moderate prudence.

Good to hear that, but if he's going to go with a new block, might as well go with the factory set up. Just as an FYI, not all '87-`91 blocks were roller cam. Some were still flat tappet. This is especially true for the truck blocks.

Too rusty
 

The 400 was inspected and though interesting, being bored and all, there was too much rust in the cilinder walls to be of any use.

So back to square 1.

I know Sean, that guy who sells C4 stuff. Not the cheapest but a straight shooter. Has LSx stuff too.
Bleprint Dart World all make 400s tpi421vette I think has a GM 400 block it was their HD race version (cant remember the name).
Call some machine shops, many have some stashed around the shops that are good.