http://www.mortec.com/location.htm

 

To add what I have seen and remember. If it has 3 freeze plugs on each side it is for sure a 400 block. The 400 blocks that have 2 freeze plugs have the raised round portion in the middle where the 3rd one used to be. You can see and feel them on the block. They were common in 70's 3/4 ton trucks, chevelles & wagons.

 

Thanks guys. Looks like I'll be taking a wire brush, flashlight, telescopic mirror, and reading glasses on the trip. How much stronger is the 4bolt block vs the 2bolt? Motor probably won't go much north of 5500rpm with only a mild cam, lightly ported heads, and bolt ons. Might eventually have a blower on it though. 7 to 8psi max.

 

@5500rpm I wouldn't worry much about main caps walking. I know that for high rpm and high HP, most guys used to search around for the 2 bolt blocks and then have the machine shop "splay" the other 2 bolts with aftermarket caps for max strength. With all of the new blocks "affordably" available now days, most guys find it more economical to get an aftermarket block which is already machined w/ cam bearings installed. At the kind of RPM you are looking at you'll be golden either way. Check out the Comp Magnum 280/280 (480/480). It's a fairly mild Hydraulic cam which has a nice choppy idle to it. I switched from the 280/280 to their 292/292 (.501/.501), and then added 1.6 rockers for a total of .534 lift, and it sounded real good in a 355in motor. You have to keep in mind that the 400 (50 extra C.I) is gonna be a little different as as far as sound and performance with the same cam over a 350. The 280/480 was very streetable and mild mannered (made good vacuum) in my 350 so it would be a nice D/D for a 400. All of the Comp Magnum's are nice cams, even the little .270/.470. The performer RPM is also a nice intake especially for heavier vehicles which require more tq down low. Just wanted to throw some ideas at ya.

 

On a 400, the 2 bolt is actually stronger b/c the 4 bolt pulls on the webbing created in the block and is very weak. If you have a 2 bolt and splayed it was a 4 bolt then it would be strong.

 

damn I love this place I have never seen a question go unanswered.

 

That is what i've always heard. I ran the dog **** out of a 2 bolt block solid roller for a couple years turning it 7000 with a 4 speed daily. Did a couple hundred 6k clutch dumps on slicks. The blocks are strong if you keep them under .030 over. Mine was .040" over but I was one of the lucky one's. Many crack from one of the head bolt holes over to the cyl wall. It is good to use studs with them to keep the stress down on the cyl head bolt threads.

 

Yeah. 400s a stout and sturdy motor but they're kinda' hard to get your hands on around my neck of the woods. A lot of them have been chewed up by the dirt track cars over the years around here. ( Insert Tyler's smart a** comment here)

 

ive turned them on and off from 6000 to 7200 for about 20 minutes straight several times racin