increase torque?

[jaythejug]

Hello,

I have a 66 LWB it has a 352 with a cruiseomatic and 9" rear. the only modifications that have been done to the engine are a 500cfm 2bbl holley carb and a set of long tube headers. thats it! everything else is bone stock. When driving the truck it is real sluggish on the low end especially starting off on a hill. I need to increase the torque. The tag on the 9" say i have 3.55. So what gears ratios are you all running and do you think would be my best bet. I would like to haul a small boat but it dont think it would pull it out of the water. and i want to do some burn outs! HA! thanks!

it is a daily driver in the summer and since i live in a small town i dont really care about gas milage. I just want to have fun!!!

[chris401]

Replacing or recurving your distributor timimg will help. If you still have your C6AE-R heads use the steel shim head gaskets. Some D2TE-AA heads would bring compression up. I located an Edelbrock SP2P for my 352 build. Youll probially read it is a dog manifold but it actually did well for its intended purpose - low end torque and fuel economy. I havent built the engine yet but I have talked to a few racers who used them in there tow trucks with 390s. Engines were done at 4500. Should work well for a 352.

[charliemccraney]

I would expect a 352 to be able to do a burn out and pull a boat. If it cannot, then there is something wrong with the engine or driveline. The first step is to identify the problems and fix or upgrade them. At this point the truck is 48 years old which means that there can be quite a bit that is not quite right. Once they are fixed, you will have a solid starting point but may find that you don't even need upgrades to do what you want.

[LM14]

If it's that weak, you have a mechanical problem. That truck would have been the work horse when it was new. My 352/2bbl is plenty fun to drive (it is a 5 speed but the auto should actually have more bottom end grunt than the 5 speed). Try a good tuneup, leakdown, check the distributor as mentioned.

Another possibility is that somebody has changed gears at some point and you have a 3:00 gear or worse in it. Check your gear ratio for sure.

SPark

[jaythejug]

thanks guys. I failed to mentioned that last spring i had the engine out and went through the whole thing. new gaskets etc.. as far as the timing. it is perfect. it starts right up and runs sooo damn smooth. I havent gone through the transmission yet. Is it true if you count the rotations of the drive shaft and the wheel then you will have and good idea of the gear ratio installed without tearing upart? im in the learning process of gearing. thanks!

[bruceandersson]

How does it respond to the idle in neutral? Sluggishness can be caused by a faulty accelerator pump on the carb.

[jaythejug]

its very responsive with the throttle. no hesitation. The truck is fast. it will scoot. I remember trying to do a burn out from a stand still and the engine was sluggish then stalled. but, if i put the hammer to it going forward it goes with no issues. i would say that my power band is somewhere around 2500 rpm +. theres just no low end. throw you in the back of your seat kind of torque. im not looking for a dragster. im sure you guys know what im talking about.

[charliemccraney]

My thought is that the 500 2 barrel is too big but perhaps other that have experience with it can speak up. I'd go for a similarly sized 4 barrel. It should be more responsive, you still have the additional flow if needed and I know you don't really care, but mileage will probably increase.

If the 500cfm carb is a good match for the engine, then the headers and dual exhaust should help a lot and it points to a tuning issue, assuming there are no problems with the engine or driveline. Are you sure it doesn't have an aftermarket cam? Is the idle pretty tame and the idle vacuum pretty high?

[jaythejug]

I do have new dual exhaust attacthed to some long tube headers. That alone made a big difference. I will check the carb again. I do believe that the 600 cfm was going to be too much for my set up and thats why i went with the 500cfm. I would like a 4bbl. but, i would rather spend the money getting all the bugs out of the drive line first then spend the 500. on a new intake manifold. and another 400. on a carb. and then a cam, and then............... haha!

what rear end gear ratio's are you all running out there? and knowing what i have any sugestions?

[charliemccraney]

I have a 3.70 but want to try a 4.11. However, my engine is quite a bit different than yours (besides being in an entirely different family) and needs the shorter gears. I don't plan to pull or haul much with it. I would think that the 3.55 will work pretty well for a stock 352 with bolt on mods.

Out of curiosity, what ratio does the VIN tag indicate?

[chris401]

You can count the rotaions on axle if both wheels turn. If one turns slower than the other you wont get an accurate ratio. I belive FE F100s commonly came with 3.55. On todays gas initial timing should be 12-22, with vacuum advance hooked up at around 2300rpm timing should be 44-48.

[LM14]

My '62 has a 4:11 and my '66 has a 3.25. The '62 was a 6 cyl truck and the '66 has the original 352. I have a 500cfm Holley 2bbl on my 352 and no problems and 17 mpg. The 5 speed makes a huge difference though. I would suggest a 3.70 gear, that's what I had in my '57 with a 278/C4 combo. It pulled good but wasn't great for a lot of highway cruising.

The 352 won't rev quick, it's the nature of the beast. It should have good torque and the auto actually multiplies the torque for you. My guess is either somebody changed the gears or you are way lean after changing the exhaust.

Play with timing, check for it being lean, make sure it's properly tuned.

SPark

[jaythejug]

well, the more i think about all of your comments and advice im leaning towards starting from scratch with a recheck on the carb and timing. I may have overlooked something. the way it acts does seem like a fuel delivery problem more than a gearing problem. thanks for all your help. its going to be awhile before i can post my results cause its snowing mad in northern MI. and my truck has no corrosion on it and i want to keep it that way.
Thanks Again!

Im still interested in what everyones gearing is and how they use it?

[LM14]

What size rear tires?

SPark

[Hoofbeat Racer]

gearing...was 3.25s then 3.70s with 28" tires. Now 4.11s with 30" tires, will let ya know in a few months how its working out

getting less street friendly every day but soooooo much fun!!!

[charliemccraney]

I'm running 275/60-15 which come out to about 28"

[Toyz]

gearing...was 3.25s then 3.70s with 28" tires. Now 4.11s with 30" tires, will let ya know in a few months how its working out

getting less street friendly every day but soooooo much fun!!!

We just finished putting 4.11's in Dale's truck; can't wait to see how it works. At least we don't have to wait for the snow to melt!
Hopefully, the 4.11/ Gear Vendors combo will yield the best of both worlds!
Paul

[chris401]

The 65 F100 has 275/60 R15, 3.70 ls gears 390 FE. It was fun to drive.

[BarnieTrk]

My :
I agree with CharlieMcC --- I'd switch out the 500 2bbl for a smaller Autolite 2bbl carb. I ran a 500 Holley 2bbl on a 390 and it was boggy just off of idle until about 1800-2000 rpms, then it would plane out. The 500 has two BIG holes to pull air through and the venturi effects in a big hole don't get to working too well until the rpms are up some. That is why they are a favorite carb on many circle track cars.... I'd bet if you borrow a good 2bbl Autolite, I'd bet you'd be happier with it. Then sell that 500 Holley to some circle track racer and be $$ ahead!

BarnieTrk