If its a work truck why not swap in a ford straight 6.

 

All of this is pointless. You will spend a lot to put any other engine into that truck. It will take years to recoup those costs with the savings of a few mpg.

Kinda like driving 10 miles to save two cents a gallon over the closest corner gas station, not worth the trouble.

 

Amen to that Better off snatching up another 400 and do the basic bolt on power mods (intake, 4bbl, headers) or buy the motor mounts and drop a 460 in. It'll leave you way ahead in time, cost and available power. 350s are a great car motor, but are lacking power for a good work truck vs a diesel or BB.

 

L98, 245 hp 350 lb-ft torque, bone stock... you sure?

*ONLY* The 460s from 80-91 are breaking either of those numbers..

The later diesels beat it on torque as well.

 

Bring the rpm numbers into the equation also.

 

Sure thing.

245hp @ 4000 rpm,
345lb-ft @ 3200 rpm.

Sorry about being off by 5, I was quoting from memory.

The TPI setup is known for being torquey, it's a long-runner setup. Most vette owners hate it because it won't spin much past 4500 rpm out of the box.

 

Please quote the Ford torque/rpm numbers also(I don't have them). It does matter, a truck tows better with torque in the lower rpms.

Not saying you can't tow with a smaller engine, but you will have to wind it out, and have lots of gears to keep it pulling. Looks like the Chevy engine would be happiest pulling a load along the interstate at about 3000 rpm. You know and I know that's a lot, and not good for fuel mileage. That's why chevy also makes the 454.

If this truck is going to be running around unloaded most of the time, I can't argue the 350 would be the best engine, putting it in overdrive to lower the revs, but pulling it out of overdrive for the occasional SHORT haul job.

 

I missed the TPI part in the OP. My knowledge of 350s makes it up to the late 80s TBI motors. My Ford 400 with just the bolt-ons would out pull the stock 88 2500 with the same gear ratio for work loads, no contest. But stock to stock, my money probably wouldn't be on the 400...

I'd still say if someone's putting the time and effort into an engine swap in a dually work truck, you could come out ahead with a bolt in replacement. Or for the fabrication and radiator replacement that are already involved in the Chevy swap, do a few more mods and drop in a diesel for torque and mpgs.

 

Ok, tq, rpm, I was actually hoping the conversation was going to turn into this direction

400ci engine



750cfm edelbrock carb

Edelbrock aluminum manifold

Comp Cam of some wild sort

Rhoads Lifters

Rear end gear is 3.73, I thought it was a 4.11 but thats what the code on the door revealed.

SO maybe the cost effective thing to do is to check compression on all cylinders and to do a tune up

Maybe it is the cam that is giving me the problem. Maybe it is too wild of a cam. I should find a stock cam with solid lifters and see if that brings the tq curve down back where it should be.

truck to truck, my 5.4L 1998 Feels like it can pull more. I pulled a car on trailer with the 81 and it wouldn't go above 55mph and i swear I could see the fuel gauge drop down to E.
I am pretty sure that a chevy 350 could outrun this truck right now.

Finding a diesel motor interests me but where in heck would you find one? U pull yards around here only carry Gas. what would be required to change on the truck (Gas to Diesel?) How much Efficient would it really be (Gas Vs Diesel?) plus wouldn't it be worth my time to find another one with 4x4 with a diesel so I could put a plow in front of it?

 

Andrew,

Please fill out the rest of your profile so we can see where you're at (click User CP in top-left to do it).

IMHO 750 cfm carb is too big unless you're running at 6,000+ RPM but it will work.

If the cam has been changed, I'm assuming a straight-up timing set was also installed.

Investigate headers (tube size & length are important) to replace stock exhaust manifolds.

Compression test is good, also check your vacuum readings.

Do you know if the pistons have been replaced or if anything else has been done to
increase the compression?

The 400 can be an exceedingly torquey engine, it's the V8 version of the I6 but was
de-tuned out of the factory to meet EPA emissions & fuel usage requirements.

Tim Meyer is a great guy as are people here in the 335 forum when they stop by.

 

I'd say definitely do the check and tuneup. Mine had a generic RV style cam thrown in with the stock lifters and it made good low end power. That gear ratio is going to be your weak point as far as towing with gas is concerned. Mine would guzzle fuel the rare times it was on the highway with the 4.10s, but mostly just saw around town and hauling use, so I had no complaints.

 

Do some homework on the M-blocks:

Some of the best info I'm aware of on the 'net is from a guy who seems to have
disappeared but his site has been archived:

Bubba's M Block Workshop - Clevelands Forever!

There's also at least one FTE Article on the 335-series (aka the M-blocks):
High Performance Options for the 351M/400 Engine .: Articles

Lessee what other links I have that may still work....

The 335 forum here on FTE sometimes has some really good engine guys in it:
335 Series- 5.8/351M, 6.6/400, 351 Cleveland - Ford Truck Enthusiasts Forums

Other stuff:

FORDMUSCLE webmagazine: Technical Department - 351C, 351M, 400 What's the difference?
How We Got Over 500hp from Ford's 400M Engine - Hot Rod Magazine
Ford 400M Engine Rebuild - Classic Trucks Magazine
https://www.ford-trucks.com/forums/1...-2171-a-2.html
http://www.mustangsandmore.com/ubb/D...1CIntakes.html
75 Ford LTD 400 2v project car - Ford Muscle Forums : Ford Muscle Cars Tech Forum
Building a Ford 351M, 400, or Cleveland Motor
https://www.ford-trucks.com/forums/7...ml#post6268338

 

This is just my opinion. But the only place for a chevy engine in a Ford truck is in the box while hauling a load of scrap metal!

 

This is my opinion, an engine is an engine. It seems people are more concerned with brand loyalty then anything else. Chevy vs Ford vs Dodge can be argued in circles with no resolution. I have driven chevys fords mitsubishis. They all are the same (mitsubishi 4g63 may be a little different) and not too much difference.

Say if I actually do this, this isn't really that hard of a swap
Both are V8 engines, both use a 2wd transmission
Both have been proven (actually the 400ci has received quite a bit of flack from what I have read in other threads)
The TPI manifold is a great low end manifold plus with a complete tuning system, I could have it running better then the stock ECU would ever have and probably better fuel economy because the injectors will be more efficient then a carb would ever be.

However I am willing to give the 400 another shot. It is time to do a compression test and maybe change some components around to get a better street able engine. More research is needed to figure out what components would make it not so much a race motor. What I am worried about now is how much new components like cams, lifters, headers (if that is really even needed) new coil for better spark, spark plugs, smaller carb.... Hmmm it is kind of adding up isn't it?...

3.73 rear end isn't that bad considering I have a 1:1 C4 trans right? It is running at 3000 rpm when I am on the highway which still seems a bit much when driving around. I would imagine it would be worse with 4:11 though. correct me if I am wrong.

 

First off, in that pic you posted, the vacuum advance is hooked to the wrong port on the edelbrock. Swap places with the hose and vac cap, recheck the timing, and try driving it.
As it is currently hooked up, it's actually a vacuum retard........
Oh, the trans should be a C6. Still just 3 speeds, with high being direct (1:1), minus a bit of slippage inside the convertor.