I bought a 74 dodge with a 400 ci ,a few months back and I have a few questions first, it has 108,000 miles on it, the tag in the engine compartment says it used to have a 440, although there's not way to tell how many miles on on I was wondering if there is a certain letter or number on the engine serial tag that i can match in a book, second, the I want to make 100% sure the MC is junk before buying another, when you push on the brake pedal as if normal driving it will go to the floor, but if you stomp on it it will lock the brakes, but then after a second or two it goes t floor, also one time while I was toying with it in my yard, I kept pumping the brake pedal and I got it to hold, third and most important, I've heard good things and bad things about the 400 engine, that it wants to take out the valve seals, I was wandering if anybody has had any experience with this engine, and how durable they are. I have gotten it hot once too as a guess to maybe around 220 at hottest, It doesn't seem to burn any oil and everything still seems ok, I will have a few more questions later most likely cause I have not bend around too many big blocks, fourth,the pickup itself I'd have to say is in poor condition the box is toast, and somebody who didn't know what they were doin took the dash apart, I will post pics as soon as I can, most dents can be fixed, but I'd like to know if this pickup is worth any more time, anymore details you would like to know about it, please reply with them, I'd be happy to answer, thank you for your time.

 

how do you know it is a 400? most big blocks look the same until you check the numbers on the block.
how do all the brake lines look?

 

If there are no brake fluid leaks what you are describing tells me the MC is bad. Just a note here, the brakes on our trucks are very hard to get bled correctly. Anyone here will tell you that so be patient and understand that you will have to bleed the brakes several times after you open the system.

If you take your vin to a dealer they can tell you what the truck had in it originally. Just ask them for a build sheet. As far as if the truck is worth fixing that is in the eye of the beholder. Personally as long as I can get parts or can work around problems they will probably junk my truck after I am permanently horizontal.

The 400 was a very good engine and all of the Chrysler engines had problems with valve seals going before everything else in the engine. They aren't that hard to replace with the engine still intact in the vehicle.

My engine has been hot before also. I can't tell you how many times I have seen the gauge pegged out after pulling loads up the mountain. These trucks take a licking and keep on ticking.

 

That's what I did to know it's a 400 check the number on the side, I have run the vin in a book that's how I know it was supposed to be a 440, the brake lines aren't spectacular, but for now I'd say there all right, mostly a little surface rust, the fact I find funny, is that me and my brother have about 6 of these old dodges and I've never seen the master cylinder go out of one, that's why I wasn't for sure, I completely agree bleeding the brakes aren't very fun, I usually have a second person to pump the pedal, I bought it for 325 $ everything mechanically is ok( rear end, trans,engine,ballpoints,driveline,etc) that's all pretty good it's just the inside of the dash with vacuum lines and wiring, box is terrible, but the cab can be saved, no rust on cab except for about an inch hole in floorboard, but I took a hammer and best around it it's still strong, once again thank you both, this is my third or fourth post, and you have helped me with them all, I very much appreciate it, thank you for your time.

 

400 motors are great. The one downfall IMO is the compression. It's a little low at 8.2 to 1. If you are going to get some head work done, take it in for a valve job and have them mill it .020 (assuming it's stock) and the intake face to match and that should get you near 9 to 1 compression which is still very streetable. I've known several people that like the cast crank 400's better than the cast crank 440's. They feel faster and a lot less weight. Definately a keeper.

 

Yea, the 400 has a 3.38 stroke and a 4.34 bore, the short stroke helps it rev faster and that's why there not known to break cranks, on the other hand, I wish it had a solid steel crank instead, for now I just wanna get it on the road, thanks for your comments.

 

What is the timing suppose to be for a 400 with an automatic, would it be the same as a 318, 16 TDC?

 

10-12 btdc

 

Thanks, my last question for now is, what can I expect for gas mileage, it's extended cab long box 2 wheel drive automatic trans and a 3.20 or 3.55 ratio in the rear end, 2 BBL Holley on the 400, dual exhaust, I heard it helps a little too.

 

My best guess would be around 10-12 MPG.....Of course that would also depend on how you drive it?? If you keep your foot in it alot, It could go as low as 8-9 MPG...Drive it like it might break at any moment and you might see 13-14.....Just my best guess....Someone else might have a better idea??