C6 Torque Converter Suggestions?

[HDxLoki]

I'm currently rebuilding the 390 FE out of my Grandfathers old F-250. I'd like to throw a new torque converter on the C6 help aid putting the power to the ground. All the parts I've been going for are aimed towards mid range power. Trying to make this truck a healthy streetable weekend driver. As far as "power parts" go this FE will be sporting a complete rebuild, bored .030" over, balanced internals, Edelbrock performer RPM intake (7105) and heads (60065), Howard's hydraulic roller cam 278/272 (250705-10), 1.76 adjustable rocker ratio, Doug Thorley long tube headers, 2.5" dual exhaust with X-Pipe, and probably topped off with a Holley/Quick Fuel 750CFM Carb (still hunting for the right carb). The trans is a stock (for now) low milage C6 and a Dana 60 rear end with 3.73 gears. The two torque converters I've been looking at are made by Hughes Performance (1.850" Crank Pilot & 11.5" bolt circle) from their Street Master line one being a 2,000 RPM stall and the other a 2,500 RPM stall. If you have any recommendations, experience, or thoughts I'd love to hear them! 

[My427stang]

You won't need a ton of converter with that cam, however, a little bit will help torque multiplication. Also realize that the heavier the vehicle, the higher it stalls. With that being said, I like Hughes at 2000, it will likely be a little looser in an F250.

I would also push you hard to go with a Transgo shift kit in that, they work well, are cheap, and really tighten up the pressures to allow clutches to live long and happy. Just remember to hunt down Type F fluid for original C-6s as the universals, really aren't

Last, as an old FE builder, some comments

1 - Look closely at your header flange compared to your heads. The Edelbrocks have an early passenger car/CJ high exhaust port. All trucks after 66, have a unibody/truck head with a low exhaust port. The port itself, not the bolts, is about .250 lower, and if the headers, heads, and gaskets don't all match, either the top or bottom of the port doesn't compress the gasket and will leak sooner or later. Sometimes you can slot the header bolt holes and slide it up, FPA makes the right header flange but often needs the pass side of the frame rolled or notched slightly. Just look close and if they aren't the same, need to get them that way

2 - As far as a carb, my go to carb is the 780HR, it works on almost anything, and not the cheapest, but they are just no-nonsense. Last one I used on a 461 made 568 HP at 5750, and we have used them on mild 390s, 445s, you name it. With yours, you could drop back to the 680 cfm version, you are right on the edge, but I wouldn't be afraid of either 680 or 780 knowing that carb and with your combo

https://www.jegs.com/i/Quick+Fuel/793/H ... Categories

3 - 2.5 exhaust is nice, and likely enough, but I have been going 3 inch mandrel bent for a long time. Header primary tubes can be too big and affect torque, but once you get to the collector you really want to match the collector ID and try to fool the engine into thinking it has open headers. So if building an exhaust, 3 inch with an X, and a nice dual system with absorption mufflers (Magnaflow, Borla ProXS, or really nice and cheap...Jones Full Boar) will make a lot of power and no loss in torque despite people erroneously applying header primary pipe sizing to intermediate and tailpipe sizing

4 - The Howards lifters are Morels, and the best ones out there right now. However, be sure to run a 10w30 oil not a thicker oil. Morel uses very tight tolerances and can hang a lifter if the oil is thick. VR1 or Penngrade 10w30 is real good, and we are able to spin them high with that oil and those lifters at proper preload (I like between .050 and .060)

Nice choice of parts

[DuckRyder]

Agree with above of course, a stock FE truck converter will likely flash stall in the 1800 range.

In addition to the trans go kit, you might want to remove the additional weight in the governor and possibly even drill the main governor weight, if you search around you should be able to find the TSB relating to GT Mustangs (maybe others too) that goes you the specs for drilling it. Depends how high you want the revs before it forces a shift.

[HDxLoki]

You won't need a ton of converter with that cam, however, a little bit will help torque multiplication. Also realize that the heavier the vehicle, the higher it stalls. With that being said, I like Hughes at 2000, it will likely be a little looser in an F250.

I would also push you hard to go with a Transgo shift kit in that, they work well, are cheap, and really tighten up the pressures to allow clutches to live long and happy. Just remember to hunt down Type F fluid for original C-6s as the universals, really aren't

Last, as an old FE builder, some comments

1 - Look closely at your header flange compared to your heads. The Edelbrocks have an early passenger car/CJ high exhaust port. All trucks after 66, have a unibody/truck head with a low exhaust port. The port itself, not the bolts, is about .250 lower, and if the headers, heads, and gaskets don't all match, either the top or bottom of the port doesn't compress the gasket and will leak sooner or later. Sometimes you can slot the header bolt holes and slide it up, FPA makes the right header flange but often needs the pass side of the frame rolled or notched slightly. Just look close and if they aren't the same, need to get them that way

2 - As far as a carb, my go to carb is the 780HR, it works on almost anything, and not the cheapest, but they are just no-nonsense. Last one I used on a 461 made 568 HP at 5750, and we have used them on mild 390s, 445s, you name it. With yours, you could drop back to the 680 cfm version, you are right on the edge, but I wouldn't be afraid of either 680 or 780 knowing that carb and with your combo

https://www.jegs.com/i/Quick+Fuel/793/H ... Categories

3 - 2.5 exhaust is nice, and likely enough, but I have been going 3 inch mandrel bent for a long time. Header primary tubes can be too big and affect torque, but once you get to the collector you really want to match the collector ID and try to fool the engine into thinking it has open headers. So if building an exhaust, 3 inch with an X, and a nice dual system with absorption mufflers (Magnaflow, Borla ProXS, or really nice and cheap...Jones Full Boar) will make a lot of power and no loss in torque despite people erroneously applying header primary pipe sizing to intermediate and tailpipe sizing

4 - The Howards lifters are Morels, and the best ones out there right now. However, be sure to run a 10w30 oil not a thicker oil. Morel uses very tight tolerances and can hang a lifter if the oil is thick. VR1 or Penngrade 10w30 is real good, and we are able to spin them high with that oil and those lifters at proper preload (I like between .050 and .060)

Nice choice of parts

I cannot thank you enough for the response! Just that post alone answered so many questions I had! I just ordered the Transgo kit for my C6 after being on the fence about it for years. With your reference to the Hughes 2000 TC saying it'll be looser in my application. Would I be better off staying with the stock or similar stall converter? One I was looking at as well is a Hughes Tow Master Series and according to Jegs it features a 1800-2000 stall and is made for trucks. Although I think this trucks heavy towing days are over. https://www.jegs.com/i/Hughes-Performan ... W/10002/-1
I've had that Quick Fuel 680HR in my summit shopping cart for a while now and been leaning towards that one. When I was looking again at the Quick Fuel HR series I found they offer a 735CFM (HR-735-VS) which would be a good middle ground between your two recommendations. Luckily in my town we have a very reputable carburetor shop so I'd like to have them dial in what ever carb I go with and rejet if need be.

[My427stang]

I think I would do either converter, pick the cheaper one.

As far as the carb, same rule, the 680 will be plenty, the 735 will be good too, whichever cheaper. Like I said I make almost 600 HP with the 780 on stroker 428s, any of those carbs will happily feed the truck, go by price.

[DuckRyder]

For the uninitiated that cam is:

Camshaft, Retrofit, Hydraulic Roller Tappet, Advertised Duration 272/278, Lift .525/.525, Ford, 352-428 FE (Duration at 050 inch Lift: 219 int./225 exh.) 110 LSA and a 106 ICL.

Stated Basic RPM Range: 1800 to 5400

It is a pretty mild cam.

In a heavy truck with fairly tall tires and a 3.73 I think it would not go above the 2000 stall converter, the tow master is likely to behave quite like a OE converter IMO.

I've run a 2000, 2500, 3000 and the present "fuel master" (1600 or 1800 IIRC) and I sorta wish I had just kept the stock one. If your stock converter is low miles and was working, I'd be inclined to keep it if it was me.

At least call Howards and Hughes and see what they have to say.

Also, I think mine has a trans go kit in it (Might be Broader) and with the stock governor it shifted about 4500-4800 rpm, you can pull the governor weights without dissembling the transmission on a long bed, just pull the tail housing...

[My427stang]

Good advice there from experience, and let me add two points

1 - Duck has significantly more cam than you, so if he liked the tighter converter, you likely will too with a shorter cam
2 - He has less gear than you, which given it's so close, likely a wash, but more of the same. If his big cam still wanted less converter with the taller gear, yours will be happy too

I do think a 2000 rpm converter is still decent compared to where Fords stall, especially with 55 degrees of overlap and the bigger cross section heads and intake manifold. That combo will not be ornery, but will like a little stall to get things going, regardless...Duck's practical experience with miles on the specific vehicle is invaluable.

That being said, input from Howards would be input...I am not particularly impressed by any cam grinder's use knowledge and I do a lot of custom cams. Your head and intake change alone changes the personality of the engine compared to an iron headed stock intake engine, so they become limited quickly at the cam tech line

Hughes or Broader, if you give them the weight information, gear, tire size, and cam specs, can likely get you MUCH closer.

My gut says you have the answer already 1800-2000 stall in your specific vehicle. Note the caveat, in your specific vehicle....that's where the good converter companies come in, not Summit or Jegs, Hughes or Broader can estimate where their converter will stall with your combo. I would use 375 HP and 450 ft lbs of torque as an estimate, and 13 inches of idle vacuum if they ask. The torque, gearing, vehicle weight and tire size being key.

Would love to hear what they say

[HDxLoki]

Good advice there from experience, and let me add two points

1 - Duck has significantly more cam than you, so if he liked the tighter converter, you likely will too with a shorter cam
2 - He has less gear than you, which given it's so close, likely a wash, but more of the same. If his big cam still wanted less converter with the taller gear, yours will be happy too

I do think a 2000 rpm converter is still decent compared to where Fords stall, especially with 55 degrees of overlap and the bigger cross section heads and intake manifold. That combo will not be ornery, but will like a little stall to get things going, regardless...Duck's practical experience with miles on the specific vehicle is invaluable.

That being said, input from Howards would be input...I am not particularly impressed by any cam grinder's use knowledge and I do a lot of custom cams. Your head and intake change alone changes the personality of the engine compared to an iron headed stock intake engine, so they become limited quickly at the cam tech line

Hughes or Broader, if you give them the weight information, gear, tire size, and cam specs, can likely get you MUCH closer.

My gut says you have the answer already 1800-2000 stall in your specific vehicle. Note the caveat, in your specific vehicle....that's where the good converter companies come in, not Summit or Jegs, Hughes or Broader can estimate where their converter will stall with your combo. I would use 375 HP and 450 ft lbs of torque as an estimate, and 13 inches of idle vacuum if they ask. The torque, gearing, vehicle weight and tire size being key.

Would love to hear what they say

Update:
I completely removed the trans from my truck this past weekend to clean off the almost 50 years of grime, dirt and oil. While it was out I thought I might as well have the trans gone though... I figure it's cheaper to fly first class in the long run. Plus throwing a mild 390 in front of a bone stock 48 year old trans with over 100k miles wouldn't be the smartest move.

Dropped off my trans at a local shop that's been around forever plus I know a lot of their happy customers. I gave the owner of the shop my engine specs, gearing, tire size, etc. to have the trans rebuilt accordingly. So it'll be a complete overhaul to handle the rebuilt motor. Plus he's throwing in the transgo kit for me, a billet servo, and a few other things that went way over my head.

As far as the converter they're having my old one rebuilt to 2000-2200 stall with my given weight, specs, gearing, cam, etc. Ends up being a tad bit cheaper than one of the hughes TCs and the whole trans will be under warranty. In addition I'll choose to support my local good reputation businesses over the big brands any day.

It's funny how something as simple as trying to track down what I thought to be an exhaust leak ended up being a burnt valve. Next leading to an engine rebuild, then leading to a trans rebuild. I guess you can't put a price on sentimental value!

[yellercat]

Hey HD; went a very similar route with my trans, near to the word.
This one had been rebuilt about 12 years ago, but asking around it seems that the 'rubbers' in these transmissions are prone to erode over time; so that really compelled me to take it in to a local also. Awaiting return to continue the build.

[My427stang]

Thanks for the update, looking forward to hearing the results!

[HDxLoki]

Thanks for the update, looking forward to hearing the results!

I know its been a bit but I finally got the rebuilt engine and trans back in the truck. As far as the trans and torque converter go, they're perfect! Firm positive shifts with the shift kit and billet 2nd gear servo. Adding a little bit of stall on the TQ with 3.73 gears gets the truck moving out of the hole quick now. Lastly I appreciate the recommendation on the carb, the QFT 735 CFM bolted right on and took very minimal tuning to get the truck drivable. I do plan on taking it to my local carb shop and having it rejetted and the power valve swapped out after pulling my plugs and seeing they're a bit on the dark side. Here's a video of it running. https://www.reddit.com/r/BumpSide/comme ... &context=3