i have a '66 with a mid 80's 300 straight 6,(what looks like to me)a 3 speed toploader, and original rearend. i was told that the trans and rearend were original when i bought it. here's the question. when i reach about 55-60 it sounds/feels like somethings stopping me from going an faster. i know that the 300 has more than that. i also think the trans would handle going faster(not much though, i know it a 3 speed). so i think it need to rebuild the rearend and put taller gears in it. any insight would be helpful.

 

Welcome to FTE

Personally I wouldn't drive one of these trucks over 60 MPH in today's traffic, because the ORIGINAL drum brakes are just terrible.

They were barely acceptable for the 1960's, but not by modern standards.

After one panic stop, the brakes fade to nothing.

Go thru a deep puddle of water, you won't have any brakes.

Before worrying about going any faster...you should swap in a set of front disc brakes.

I have a '65 F100 I bought brand new, which still has its original drum brakes...so I ain't just a whistling Dixie!

 

thats in the works but i want to keep as much of the original stuff as i can. and i have to do it in stages so i was wondering if i should be looking for a 4 speed or just replace the rearend gears. i'm guessing you guys will say both. ha ha

 

The 3 speed transmission, as original is prolly the Ford type 3.03 3 speed manual all syncromesh transmission.

There was also the Borg-Warner T-85 3 speed overdrive (O/D) available. The cable that operates the O/D is to the left of the steering column. When O/D is present, the rear axle ratio is much lower (numerically higher) than what's used with just the 3 speed.

The rear axle could be one of three. Look at the center section, is there a cover back there, or is it solid?

If it's solid, it's the Ford 9 inch, which came standard equipment in these trucks. Two Dana-Spicers rear axles were optional.

What rear end ratio does it have?

If the ratio has never been changed: Ford put the AXLE code on the Warranty Plate, located on the left door face below the latch. Look on the second line to the right...post what the code is.

The TRANS code is also there, before the AXLE code...post that too.

Ford 9 inch: There's an ID tag on the rear axle, under one of the bolts that holds the carrier to the housing. Its usual location (if still there) is at roughly 5 o'clock.

You may want to post that too. Sometimes, if the ratio was changed, so was the tag.

 

here's what i found.

trans code-c
axle-09 (solid back) so a 9" right?

axle tag which was completely smooth on the front so i kinda had to read the impressions on the back side. and backwards.
3 70 5EB 302 (not 100% on this)

hope this is enough
thanks

 

09 = Ford 9 inch / 3.70-1 / non Limited Slip / 3300 lb. Rear Axle Capacity

C = Ford Type 3.03 3 Speed Manual all Syncromesh Transmission

3 70 = 3.70-1 / 5EB = Assembled the second week (B) of May (E), 1965 (5) / 302 = Plant Code

 

There's no reason that a transmission will have a speed limit.

"i also think the trans would handle going faster(not much though, i know it a 3 speed)."

Assuming there are no bad bearings or broken parts and it has the correct oil in it, the transmission will handle any speed you could demand of it. Driving the truck at 150mph won't bother it.