Hi,

I have a 1978 Ford Thunderbird that has a 351M engine in it. I want to pull it out and possibly drop it into a 73-77 F100 truck. I am not sure what size tranny is in the T-bird, but I am going to pull it too.

Would it be better to build it as a 351 or a 400?


Thanks,

Chris

 

400 all the way. If i was told correctly...the only difference is the crank. go the extra mile and make it a 400

 

The crank and the heads are different. If your going for performance go ahead and change the timing chain and sprockets for a nice aftermarket set and throw in a cam. Ive been contemplating the same thing but lack the funds or time.

 

The heads are different? First time I heard that!

 

Yeah, I don't think the heads are any different, but the crank is. The 351M is just a destroked 400, so why not put the stroke back where it belongs? Add a straight up timing kit, new cam, headers and good carb, and it'll make one hell of a difference.

Now, if you want to be a little looney like me, then go ahead and get the CHI heads, and have the block built out (to include upgrading to 4-bolt main caps) by a good machine shop like Tim Meyer's, and add all the other doo-dads like intake, water pump, fuel pump, etc, etc, etc. Granted, it'll cost a bundle, but it'll be quite the beastie in the end.

The cheapest solution for the money is to just put in the 400 crank, massage it a little with timing set, cam headers and carb, and you'll get an engine that has good power. That's my $0.02 anyway.

 

A couple of questions.

Would this get more hits or replies if it were in the appropriate engine forum?

Would I have to change out the crank if I did make it a 400?

I was thinking of putting a new intake on it to accommodate a 4-barrel carburetor, headers, flowmaster true dual exhausts, new cam, and other small modifications. I am looking to pull the engine in the next few weeks and will have it on the engine stand for rebuilding.

Would all of the modifications that I want to do, make it a good engine?

 

Those mods would make it a good engine. 400 has a longer stroke crank, rods I believe are the same but different pistons.

 

To answer your question Cdawley, yes, you'd have to change the crank...and since you'd be in there anyway, I'd advise to change the pistons out to a set of the flat tops that Tim Meyer (TMeyer, Inc.) has, which will bump up the compression as well. That, with the mods you've listed, should make for a pretty healthy plant.

edit: you might want to talk to Tim about the pistons, and possibly have them dished to whatever compression ratio would serve you best. if you want to stay on regular gas, then you don't want the compression that high, versus putting super or race fuel in the tank, then a higher CR would be beneficial. According to Tim, my plant runs just shy of 11:1, and takes super unleaded, but I also have the aluminum heads, which should reduce temperatures enough not to have any ping.

 

Make sure you post a build thread of your motor. I have a 351m also and want to do the 400 supe-up!!!

 

ok. the 351M/400 has the most potential per cubic inch of any motor that ford built. thats why its won the jegs engine masters challenge the last two years in a row, and took second the year before. simply changin the timin gear to correct the 6 degrees of cam retard puts the 400 at very similar numbers as a stock 460. throw a good, say level 2 or 3 cam at it, four bbl carb and a set of headers and say hello to over 300 HP and 400 ft/lbs. add some good heads, a lumpier cam, and few compression points and your between 375 and 450, and 400 and 500 and still have a streetable motor.

TMeyer, Inc. Precision Automotive Machining

400 Ford: Peformance From Another Aftermarket

FordMuscle - SBF 454 Build - Circle Track Ford

the last two links are on tim meyers page.

 

back in 99 when i had a 79 shortbed 4wd i ended up building the 400 a little bit. when i bought the truck the motor was rebuilt and they installed cleveland 2v heads on it with an edelbrock performer intake and 600 holley. im not sure what pistons it had in it as i never took the heads off.

what i ended up doing out of pure luck was,

i bought this cam Crane Cams 133052 - Crane Energizer Cam and Lifter Kits - Overview - SummitRacing.com along with the right springs, locks and retainers. and also a fitting to stick in the spark plug hole to change the valvesprings using compressed air rather than taking the heads off.

this intake Weiand 8010 - Weiand Action+Plus Intake Manifolds - Overview - SummitRacing.com

and rebuilt the holley carb that was on it and also installed longtube headers and true dual 2 1/4" exhaust dumped at the axle with thrush glasspacks.

all i have to say was that was a nice well noticable improvement than what it had when i bought the truck. it would hang with factory fox bodies for the first 50-65 ft shifting at 6500, granted the truck had 4.56 gears and 33's. man i miss that truck.

 

here are some dyno pulls done on a tmeyer 400 build back in 2005 on 87 octane.

TMeyer, Inc. Precision Automotive Machining

 

Cool. I like the suggestions. I will post another topic over in the engine thread, because I want some ideas about rebuilding the engine. See y'all over there.