318 to 383/440 swap and K member

[Sonny]

This is a pic of my engine compartment when I swapped my 318 for a 360. Now I am itching for a 383 or 440 for my ‘70 Belvedere. Will the BB bolt to this K member? I know I will need a new trans and drive shaft mods. I already replaced the leaf springs with 440 springs and replaced shocks with BB rated shocks. It’s an AC car and has the 26” radiator. So does it bolt in and are there any other large pitfalls I am missing?

Note: this is a car show/Power Tour cruiser. Not a race car, so I’m hoping I can avoid the torque box and anybody rear end change issues. I think it’s a 7 3/4 rear end.

 

[moparmarks]

Yep, A V-8 K-frame will take a 273-440. Hemi and /6 are different.
I have a set of BB mounts if your interested.

 

[burntorng70]

The k frame will work fine, all you need are the metal mounts that bolt to the engine. They are around 150 bucks from Mancini Racing. You will most likely find the limits of that rear end fairly quickly, so plan on an 8 3/4 upgrade soon.

 

[moes]

bigger torsion bars, especially if they are the original 318 bars that came with the car and are over 45+ years old. BB motor 200+ lbs heavier that a SB. You will also need BB exhaust maniolds to go with the new motor.

 

[wyrmrider]

If you have a small block 727 then drive shaft does not have to be changed tillyou change the rear end
904-999 then yes- might change rear end at same time although rear end will last on street tires with an auto and I'd go to the larger size u-joints and as I have said elsewhere use only Dana Spicer or Factory- electro/ induction hardened joints leave you stranded in a bad place in the middle of the night or worse
x2 on the torsion bars

 

[peakandscoot]

I have a 62 Fury that has a 383 and this is what we have. Like burntorn70 said they sell them at Mancini. Mine are 55 years old but are identical.


These brackets are required IN ADDITION TO the mounting brackets and insulators used for B/RB installation in '63-65 B-Body.

 

[moparmarks]

I have a 62 Fury that has a 383 and this is what we have. Like burntorn70 said they sell them at Mancini. Mine are 55 years old but are identical.


These brackets are required IN ADDITION TO the mounting brackets and insulators used for B/RB installation in '63-65 B-Body.

View attachment 597345

Actually those are for your 62 only K-frame. 63-72 don't need those.

 

[WP29440SE]

bigger torsion bars, especially if they are the original 318 bars that came with the car and are over 45+ years old. BB motor 200+ lbs heavier that a SB. You will also need BB exhaust maniolds to go with the new motor.

so your saying I would have to upgrade my .92 SB bars to .96 BB bars just to drive around my 220 lb girlfriend and her 250 lb brother in the backseat? not to mention my 210 lb fatass. I hardly think so. my 318 bars work just fine with all of us and that 750 lb 440 .

 

[PP1RT]

I have a 62 Fury that has a 383 and this is what we have. Like burntorn70 said they sell them at Mancini. Mine are 55 years old but are identical.


These brackets are required IN ADDITION TO the mounting brackets and insulators used for B/RB installation in '63-65 B-Body.

View attachment 597345

He has a 70. Different deal than what you have.

 

[moes]

so your saying I would have to upgrade my .92 SB bars to .96 BB bars just to drive around my 220 lb girlfriend and her 250 lb brother in the backseat? not to mention my 210 lb fatass. I hardly think so. my 318 bars work just fine with all of us and that 750 lb 440 .

Sorry I should have been more percise on the weight and I should have said BB motor including the BB 727 transmission weight, most 318 cars came with the 904 transmissin which is around 35lb lighter than the BB 727. SB 360 motor 525 lb, BB 440 670 lb plus 35lbs for the BB 727 motor would weight is a total of 185 LBS. SO I WAS 20 OR SO LBS OFF. I don't know where you got the 750 LB for a BB motor? You must have some Big *** 440 Really!! Most of these cars start to sage in the front and rear after 45+ YEARS OF USE and you add in the weight of the BB motor and 727 transmission and the front end sages even more and the car bounces up and down even more, that is why I suggested new bigger T bars!!! And there is a weight difference of 10lb or so between the bigger 440 exhaust manifolds and those little 318 exhaust maniflods he is using now, it all adds up to more weight on the front end.

 

[Sonny]

Looks like l need to start a new parts pile!
Thanks for the great advice!
I do have the 904. Will I need a different trans support brace for the 727 too?

 

[wyrmrider]

big block does not use the trans support braces
polyurethane rear mount if yours is bad
bottoming out with weak torsion bars bangs up your alignment fairly quickly and can bend k member
drag racers can use the 6 cyl bars but usually up lock shocks prevent bottoming out
1.1 inch aftermarket if you want to corner with today's wide wheels and (lower profile) tires

 

[moes]

Looks like l need to start a new parts pile!
Thanks for the great advice!
I do have the 904. Will I need a different trans support brace for the 727 too?

Sonny you can use your 904 transmission crossmember as it is the same for a 727 transmission, the transmission mount is 23 1/2 inches from the front for both transmissions. You just need a 727 driveshaft and yoke or shorten the 904 and the different yoke for a 727 and have it balanced, the 727 has a longer tailshaft then the 904.

 

[WileERobby]

so your saying I would have to upgrade my .92 SB bars to .96 BB bars just to drive around my 220 lb girlfriend and her 250 lb brother in the backseat? not to mention my 210 lb fatass. I hardly think so. my 318 bars work just fine with all of us and that 750 lb 440 .

You're forgetting the weight of the sack of donuts everyone's scoffing inside the car.

 

[WP29440SE]

You're forgetting the weight of the sack of donuts everyone's scoffing inside the car.

not to mention the 9 double cheeseburgers, fries and ice cream. those poor 318 bars are incredibly stiff and solid for all that weight up front.

 

[wyrmrider]

thanks for the chart moes
better than my scribbled notes
I'm going to add the diameters at teh back to aid in tunnel mods