Stroke a 396?

[6.50camaro]

I was told years ago by an engine builder that you can put a 454 crank in a 396 and use stock pistons with a 6" rod from a 409. Not sure if it's true but there was some kind of article in one of the car craft mags about it.

BBC rods are 6.135, 409 'W' rods are 6.000.

Using the 409 6.000 rod with the 1.765 ch 396 piston and a 4.00 stroke crank my calcs show a 9.765 height to 0 deck. Std 6.135 bbc rod + 1.645 ch 454 piston + 4.00 454 crank = 9.780 to 0 deck , so that is .015 shorter. Dan

[tenxal]

Using the 409 6.000 rod with the 1.765 ch 396 piston and a 4.00 stroke crank my calcs show a 9.765 height to 0 deck. Std 6.135 bbc rod + 1.645 ch 454 piston + 4.00 454 crank = 9.780 to 0 deck , so that is .015 shorter. Dan

Correct. With the 409 rod, there's also the issue of the 2.000" rod journal versus the 2.200" BBC.

[69427]

Another thing with the small bore is that a modern cylinder head chamber will overhang the bore/block. The top of the bore can be relieved some with out getting into the top ring.

[Ron Miller]

It is bored 90 over. KB makes the pistons using the 396 crank. I would like to put a 4.00 stroke in it somehow. Its a BBC. As of now its about 418 cid.

What parts do you have to build this combo? Are you looking to buy a kit? I have a friend that has a complete rotating assembly that he wants to sell. If you are intrested send me a P.M.

[needforspeed66gt]

I've done a ton of 4.25" stroke combos on factory BBC blocks, but I ran into serious rod to block clearance issues with this L89 '66 427 I did this week - had to notch both sides at the bottom of the bore to keep the rods from hitting like you'd do with a 383 build with factory rods...never have had this issue before in a BBC, so just be aware that it may come up with the really early BBC block castings, this one was a 3869942

[econo racer]

I have a good 396 and 454 crank. I have a good set of 454 rods also.

[ProPower engines]

I have a good 396 and 454 crank. I have a good set of 454 rods also.

Then just get a set of pistons for the bore size you have and use the 454 crank and rods.
Thats the cheapest way to get it done. The 396 and 454 rods are the same length at 6.135 so regardless you will need
some pistons but to me is just seems easier to get a 454 block and the piston options are less cost compared to a
+.090 4.125 bore.

If its just a mild build get the block sonic tested. You may be surprised and you may just be able to use a std.454 slug
The 396 block just seems like a waste to use for that type of build unless its a spec deal for class race class.
Since a sm b;lk shares the same bore size as a 396 you may be able to just get pistons for a 6.125 rod thats common
for a small block and bush the stock rods for a .927 pin. Again seems like a waste of a block but the bore is just the
hang up on the whole deal.

I have to ask why are you hung up on the 396 block??

[econo racer]

Its just being used for sentimental reasons I am going to get all the numbers off the block pad and make sure its not for some rare find. and I will mock up something 1st to make sure the block doesn't have to be clearanced massive cause if so I will probably just sell the block. I might go for a 502 block and make a 540 cid. That would be my dream motor.

[ProPower engines]

Its just being used for sentimental reasons I am going to get all the numbers off the block pad and make sure its not for some rare find. and I will mock up something 1st to make sure the block doesn't have to be clearanced massive cause if so I will probably just sell the block. I might go for a 502 block and make a 540 cid. That would be my dream motor.

Ifr ya find a 502 block then go for a 4.750 stroke. and do a 620 the shafts are the same cost as a 4.250 stroke
Pistons and rods are the same cost as well if you choose that route

[Walter R. Malik]

Its just being used for sentimental reasons I am going to get all the numbers off the block pad and make sure its not for some rare find. and I will mock up something 1st to make sure the block doesn't have to be clearanced massive cause if so I will probably just sell the block. I might go for a 502 block and make a 540 cid. That would be my dream motor.

Ifr ya find a 502 block then go for a 4.750 stroke. and do a 620 the shafts are the same cost as a 4.250 stroke
Pistons and rods are the same cost as well if you choose that route

Have you built one like that ...?
I didn't think you could fit a 4.75" stroke in a 9.8" deck height block. This would be good to know.

[econo racer]

A 4.75 stroke in a standard deck BBC

[FC-Pilot]

A 4.75 stroke in a standard deck BBC

I was thinking the same thing. I have heard people squeeze a 4.5” stroke in a standard deck, but from what I understand that was still a squeeze. Have been tempted to try it with some of my junk I have sitting around, but have resigned myself to the fact that a 4.75” with my standard junk is not going to make it.

As far as putting a 4” or even a 4.25 in a 396 block I don’t see what it can’t be done. Is it the best use of your time? For me I would not as I would put the work in a 454 block or aftermarket, but to each their own. If the block matched the vehicle then that would be a different story.

Paul

[ProPower engines]

Ifr ya find a 502 block then go for a 4.750 stroke. and do a 620 the shafts are the same cost as a 4.250 stroke
Pistons and rods are the same cost as well if you choose that route
[/quote]

Have you built one like that ...?
I didn't think you could fit a 4.75" stroke in a 9.8" deck height block. This would be good to know.
[/quote]

Yes have a build in my shop truck. Std deck 502 block +.030 over 4.750 stroke.Yes there is a bit of grinding to fit the rods but nothing more then common clearancing for an H beam rod and a bit near the pan rail in a couple spots..

[FC-Pilot]

Yes have a build in my shop truck. Std deck 502 block +.030 over 4.750 stroke.Yes there is a bit of grinding to fit the rods but nothing more then common clearancing for an H beam rod and a bit near the pan rail in a couple spots..

That does not leave much room for the ring pack. Must have had the counterweights cut pretty good as well. With a mark4 style block I would imagine the main oil passage by the pan rail would look like a sprinkler.

Paul

[ProPower engines]

Gen 5-6 blocks have the main oil galley's in a different location compared to the gen 4 blocks.
The cranks have different counter weights but in an early block they would need to be much more reduced to clear the oil galley on the lower part of the block.