700R4 Conversion

[72longstepper]

1972 GMC LWB -----350 with mild cam will be running about 300-325 HP. What torque converter do you guys recommend ? I know nothing about stall speed or lock up etc. Not going to be racing or anything like that as I am an old fart that got "caught up in the moment" and going way deeper into this project than I intended. Any help is appreciated.

[YoungPup1977]

Can you provide more information about the cam that you have. Do you have the spec sheet on the cam. This information is required to make sure you get the correct stall speed of the TC. Thanks

[72longstepper]

4.040 bore
3.48 stroke
GM 3970010 4 bolt main block
Sealed Power H345DCP hypereutectic pistons
Hastings 139 rings
MS 909P main bearing set
CB 663P rod bearing set
Durabond CH8 cam bearings
Engine Pro 3001 timing set
Engine Pro camshaft 214*/214* .450/.450" valve lift @.050" lift
Johnson HA817 lifters

[Bigdav160]

I am curious what you're going to do for cylinder heads? Those pistons really need a 64cc chamber. I don't see that cam listed in their catalog.

If it was me, I'd shoot for a stall speed around 2200-2400rpm.

[YoungPup1977]

check out this link... it indicates your torque range for your camshaft This is a engine pro link. Good Luck !!

http://www.engineproparts.com/downlo..._CamShafts.pdf

[Captainfab]

I also did not see that cam in Engine Pro's listing. However with that small of a cam, I would not recommend any stall converter other than stock for what you are using the engine for.

[YoungPup1977]

Just going by the information provided as 214 duration and using the link provided in post #5 it indicates on a stage 2 cam the torque range starts at 1800 rpm. A stock corvette TC would work just fine, they normally are in the 1800 to 2200 rpm range

GOOD LUCK on your TC choice.

[YoungPup1977]

Have you bought your 700R4 trans yet for the conversion ? If you haven't, check out the type 1 VB with the TCC shift valve which makes the engagement of the TCC much better than wiring to the 4th gear oil circuit to engage the TCC. If you need additional info on what I am talking about just ask I can provide pics and all the info you can stand.

[6T7 C10]

A medium 1600-1800 stall would be what I would do with what you described. If you get too high a speed you always have to rev it to take off plus if it is higher than your cruise rpm then you are making a lot of heat unless you activate the lockup.

[Ziegelsteinfaust]

Torque converter choice depends on rear end ratio, but must also comprise with the cam shaft as much as possible. Mix in there the intended purpose, and it can feel overwhelming.

On old vehicles running a carb especially heavier ones like trucks or land yachts. The best mpg with a sbc in my opinion is around 1900-2200 rpm. This gives the carb especially if it is a well tuned Q jet or Holley decent amount of signal to be able to properly meter fuel. It may even produce the same mpg up to 2500 because of cam timing or a combination of events. Through on 35" tires, and you may need 3000 rpm to put down enough power. Ir your truck will constantly down shift.

So since your running a th700 I assume your keeping the lock up for this scenario, and I would ru. A 2000 rpm if I intend to tow with the truck or work it enough. A 2500 if it is a play thing.

What gear ratio do you plan to have in the rear end?

Use this calculator to help you ove stuff around to suit your ideals best.
https://www.richmondgear.com/wp-cont...alculator.html

Depending on how your truck is you may want to do rear gears to dial in the combo for ultimate happiness. As they were geared to split the differences with no OD trans.

[72longstepper]

Sorry all for super late TY's for you input. Health demons reared their ugly head yet again. Just now getting back on my feet a bit. Have decided to just keep the 3 speed and put in a Hurst floor shifter/kit. Have lost to much time to do much else as far as tranny.