My 1977 F150 400ci engine performs well (certainly better than my 2004 f150 w/ 4.6), however I am trying to decide what and if there is more I can understandably do to the timing gear, cam or valve train?

The 400ci long block was replaced the summer of 2003. The long block was purchased from O’Riellys. I do NOT have the specifications for it but this is what I have. I have used since last summer pulling a 28’ travel trailer.

The engine has around 20,000 miles. Below is more information.

COLD compression test: (1) 120 (2) 115 (3) 115 (4) 115 (5) 105 (6) 120 (7) 110 (8) 105. I think this is above average.?!

625 Street Demon tuned with an A/F gauge

1” spacer

Performance 400 dual plain intake

1-3/4” long tube hooker headers

Dual exhaust, 12” resonator, single chamber mufflers, out in front of rear wheel

Cam, I tried to measure the rocker at top of the pushrod. I got .425-.450 ish, both intake and exhaust. I have no other information.

Timing chain, it could be 4 degrees retarded, I don’t know. Would they do that (not install straight-up)?

I like the truck, it does the job. I “feel” the HP and torque is nearly 300hp and 350 ft lbs. What is your estimation?

I can afford a new timing set and cam. I am wondering, is this engine worth a new cam and timing set or should I just ride it off into the sunset.
Side note, it is a 400, C6, 3.55 Detroit locker 2wd, stock tire size equivalent, pulls well but will not spin the tires on dry pavement.

Thank you for your time,
JD

 

Your compression is quite low, maybe original spec? Probably have the retarded cam timing also. You can try pushing the ignition timing up. Probably more like 250hp if that. Sorry.

 

I am thinking that the long block was probably back to stock spec. What should a 8.3 ish to 1 CR engine compression test as (cold)?

 

Not sure, someone will chime in. Setting the cam timing to zero would help. Might even raise compression a tad.

 

1977 Ford 400 was about 170 netHP at 3400 RPMs stock when new... about 210 crankHP with headers... actual compression ratio was about 7.6:1... since there were no good 'rebuilder' pistons available, your compression ratio is prolly even lower because pistons sit even lower than stock... the rebuilder may have used the stock overly retarded cam spec.s, as well, to meet emissions requirements... the cam is prolly about a 184/194 duration at .050" lift... Your added 4 bbl. carb. has prolly restored you back to stock HP or a tad higher and added a bit more high RPMs...

As is discussed in most threads here, your only real solution for more power is TMI pistons... the stock cam was too big for the stock compression ratio and going bigger cam just makes matters worse.... will give even less tire spinning torque... more cam simply requires better pistons...

I'd suggest TMI pistons to get compression ratio up into the 9's and a Summit 5201 cam of 218/228 durations for a serious boost in power and torque on a budget... anything else is just spinning your wheels as far as getting more power... TMI pistons are the ONLY off-the-shelf performance pistons available that simply go right in... 150 - 175 psi compression pressure... We're talking around 350 HP at 4500 - 5000 RPMs and 450 - 475 ft-lb torque... improved MPG...

https://www.summitracing.com/parts/sum-k5201

Also, an adjustable timing set:

https://www.summitracing.com/parts/s...view/make/ford

(You may be able to get tire spinning torque out of your current setup by making sure the secondaries of the 4 bbl. carb. aren't opening from a standstill... advancing the cam timing... carb. may have come with #62 - 66 primary jets for a 302" or 351" engine, prolly needs about #70 - 72 jets for a 400... these engines were actually 402" new, prolly 406" - 408" now, depending on overbore... maybe even larger...)
.

 

Thanks for the information Buzz!

 

You're welcome... Take a test drive in a Dodge Hemi pickup to see what your truck would drive like with better engine parts...

 

I've run the Summit #5200 in a stock 400 and the results were amazing. Stock 2 bbl intake topped with a Holley 500 cfm 2 bbl and long tube headers. In a short bed 77 F100 with a C6, it would boil the tires.

 

Rear end is prolly a 3.50... what is the diameter of your rear tires? Was the locker stock? Have you verified the rear end ratio?

 

The locker and axles are from strange engineering. 3.5 would be correct. I have pulled the same trailer with the 77 and a 2004 f150 with a 4.6. The 77 400 out pulls the 04 easily like it should.
I plan to conduct another compression test pre warner to operation temp.

 

The '77 400 prolly has more low RPMs torque... the '04 4.6L (280") prolly has similar or even more HP... whichever truck has the higher top speed prolly has the most HP... depending somewhat on gearing, of course...

 

Did you ever test both your trucks and see which one has the highest top speed?