I have a 400 that somebody bought out of a 1971 model station wagon. They were swapping into truck and it rained into the carb and locked it up. Now the engine is in my hands and it is unlocked and runs. I did not run it very long because I wanted to dig into it deeper as not to risk damging. I have the engine completely tore down at the moment and plan on rebuilding it soon with a kit. It does need cam bearings and a couple cylinders are scored a little (nothing major). Which kit is undecided, I have been looking at the Enginetech kits on Ebay, where the cheaper ones come with gaskets, pistons, rings, rod and main bearings, cam bearings, timing set, oil pump, and freeze plugs. The more expensive one comes with all of the above plus a camshaft, order specific. It is about a $100 difference so heres my question. I am probably going to take it to a machine shop to have cam bearings and freeze plugs changed so I am wondering if since Ill probably be buying pistons anyway if I should go ahead and have them bore it .030 over. Im not looking to build a stroker or anything, just trying to build a powerful engine to drop in my F250 that can pull loads without too much strain, also so i can ensure a nice smooth cylinder. So if i decide to go ahead and bore it, what does everybody recomend about the cam. Should I spend the extra hundred to get a larger cam, or leave it stock? Also, being a 1971 model, it was built for leaded fuel and i have heard a lot about people putting hardened valve seats for unleaded. Can anybody give me input on this? Any and all help would be appreciated and sorry for the long post.

 

Read some of the billions of build threads here. Tmi sells a 9.5 piston. Kits will give you the low 8ish compression the post 71 engines had. A better cam is also a good idea. You want 164 horsepower 300 something torque or would 300/400 work better on the same amount of gas?

 

I second that - talk to Tim Meyer He has all the parts you need and is the only one that has the pistons you need.

 

I read somewhat on other threads about Tim Meyer, Idk im just not sold on that yet. As far as I know, they could probably use another thorough look, but my factory pistons should be reusable. Yeah, i have read all the stuff about the 71 model 400 was the one to have with its flat top pistons and 9.0:1 compression ratio and i hate to lose that. I figured those kits wouldnt come with flat tops so Id be taking a loss there. So if I reuse my pistons, I could get by a lot cheaper by buying rings, bearings, gaskets, and timing kit seperately. But idk if thats the best option. I will probably have a better idea once I look the pistons over again.

 

I'm confused. You have a used engine with scored cylinder walls. If you have scoring you are going to need to bore the engine to get back to a round and smooth cylinder. That's because cylinders don't wear evenly, so yours aren't round. You will need to take it to a machine shop and have them tell you how far it needs to be bored. At that time you will have to have new pistons. So, why aren't you sold on getting the pistons that will give you good compression?

 

. X 3... TMeyer has the ONLY pistons to use if changing pistons...


. The "8's" compression ratio after '71 was actually in 7's... and all other pistons drop that even lower as the pistons sit still lower...


. When comparing pistons, compare the 'compression height' to Tim's piston's 1.710" height... or even KB pistons for a 351C of 1.670" height...


http://www.crankshaftcoalition.com/wiki/Quench

 

TMI pistons will increase the compression ratio over your stock 1971 400. So if you need to replace the pistons these would be the only ones to use unless you want to lose compression. Your motor being a 1971 also has better flowing heads compared the 1975+ heads. They are basically 351C 2V heads.


If you have a chance, can you post some pictures of the factory 1971 400 pistons?