C4 Bellhousing Differences???

[Mooosman]

Hey guys,

I'm building a hot rod 300 straight 6 for my 72 SWB F-100 (bought the unfinished engine project from my teacher, the previous owner), and I'm looking at transmissions right now.

This engine is going to make between 350 and 400 horsepower depending on the intake manifold I go with, and I don't think the old 3 on the tree is going to stand up to that kind of abuse for very long.

I'm thinking of putting an automatic behind this hot-rod engine, but after looking at the catalogs, I'm a little confused...

What exactly did they put the C4 behind? It's a light duty trans, so did they just put them in cars, or what? Will a beefed C4 live behind 400 hp/400 lbs of torque for a long time?

Secondly, what is the difference between the small bellhousing and large bellhousing. What does the 300 six use? And, what kind of flexplate am I going to need? I see a 157 and a 164 tooth flexplate for the C4.

Lastly, what all do I need to bolt a C4 into my 72? Am I going to have to shorten the driveshaft, replace the crossmember, etc.??

Thanks guys, I'm a Chrysler guy normally, so I don't have much knowledge of Ford stuff yet...

Nick

[splavin90]

they put c4's behind smallblock engines (240,300,302) and 351(i think)
I think that a beefed up c4 trans behind that engine would perfect.

you may want to try to look for a smallblock C6 transmission for your project. the c6 is manly a big block engine, but they did make a few small block c6's. (...but i'd just stick with the c4)
depending on what you have in your truck, and what you end up putting in. you might need to do something about that driveshaft. (my truck had a 240/c4 trans i am putting in a 302/fmx trans, and i don't need to shorten the drive shaft.)

what engine and transmission do you have in the truck right now?

[flyboy2610]

A lot of race cars use built C4's. They will handle the horsepower. You want the small block bellhousing.
You will need the correct tranny mount, and if the truck is a long bed, you will need a two piece driveshaft with carrier bearing.

[Mooosman]

The truck is a short bed, and right now I have a 3 spd column shifted manual. Will I need to shorten the driveshaft, or are C4s the same length as the 3 speeds? What about the cross member?

Lastly, can I reuse the yoke on my driveshaft?

Thanks guys

Nick,
Is waiting on pistons...

[flyboy2610]

The truck is a short bed, and right now I have a 3 spd column shifted manual. Will I need to shorten the driveshaft, or are C4s the same length as the 3 speeds? What about the cross member?

Lastly, can I reuse the yoke on my driveshaft?

Thanks guys

Nick,
Is waiting on pistons...

If you have a slip yoke (and I think shortbeds do, but I could be mistookened about that,) then a C4 from a car would work. Otherwise try to find one in a shortbed. You can use the same crossmember, but you will have to get a different tranny mount.
I don't know about the driveshaft length.

[willowbilly3]

So just how are planning to get that kind of power from a 300? Just curious because that would be a radical 300.

[Mooosman]

I was waiting for someone to ask if that power number was a typo or not...

Anyway, here's the buildup. I don't have an intake or headers for it yet, so I'm still open to options. Anyone have a 4 barrel intake they want to sell???

1993 4.9L block, .030 over
Forged crank, .020/.020
240 rods, ARP rod bolts
Keith Black #319 pistons (408 Windsor), with .070" milled off the tops. 14cc dish.
Speed Pro file-fit rings, low tension
Melling HV oil pump, screen, drive rod
ARP main studs
Cloyes steel timing set

The shortblock is pretty basic, the only tricks are the low tension rings, and the 240 rods (the 240 rods are longer than 300 rods, so it allows you to use a shorter, lighter piston).

The big power is going to come from the cam and top end of the engine. The head is a stock Ford casting, I'm not sure what year. It was ported by one of the cylinder head instructors here at the school.

230 cfm @ .700 lift
1.850/1.550 intake and exhaust valves (Manley stainless steel)
chambers reworked and head milled for 65cc chambers
Custom Comp Cams solid flat tappet cam, 248/254 @ .050, 110º LSA, .566 lift
Isky Gold Stripe double springs w/ damper, 133 seat/330 open
Head machined for 7/16" screw-in studs and guide plates
1.7 ratio big block Chevy roller rockers with Poly-Locks

You have to remember that this is a large bore/large stroke engine in stock form. If it were a V-8, it would be over 400 inches. So, when selecting a cam for this thing, you have to cam it like you would a 400 inch engine with reletively decent heads.

With 230 cfm of head flow on tap, and over 240º of duration @ .050, this engine will pull to 6500 rpm+ given a good 4 barrel or multi-carb intake and headers.

For exhaust, I'm going to go with single 3" pipe, routed where the stock exhaust goes, and exiting in the stock location. I'm going to run a big Dynomax RV muffler (36" long case) to quiet it down to as close to stock as I can get. I'm going to leave the rest of the truck looking completely stock, including the steel wheels and hubcaps.

With 375+ horsepower and a 3.70 gear in a light weight short bed truck, it should be really fun to drive!!!

Nick,
School of Automotive Machinists

I should be assembling this engine next week; I'll be sure to snap some pics for you guys.

[ranger240]

that sounds pretty sweet, what kind of carb are you looking into getting? it's gonna have to flow ALOT (for a sixbanger) I would suggest 750 cfm be the smallest you go.....but as I can tell from your post, you probably know alot more about that kind of stuff than me!!!

have you looked into building your own intake? I've got a friend that picked up 20 DYNOED horse power from his stainless equal length runner intake manifold (on a turbo fuel injected car)

[Mooosman]

I have looked into building my own sheet metal aluminum intake out of a stock 4.9L EFI lower intake, and a custom top, I just don't have the time right now to do it.

Unfortunately, ALL the off the shelf intake for inline 6s are a comprimise, as the middle 4 runners will always be a different length from the end 2 cylinders.

I'll probably end up with a single 4 barrel intake. A 650 double pumper Holley will get the job done on this thing.

Nick

[ranger240]

yeah, I forget how LONG the I-6 is it may be a better idea to go with a dual or triple 2 barrel setup for best efficiency.