swap a 396 4-speed for a 350 auto

[dirtracer]

I have a 90 silvarado, short, sport bed with a 350 auto. I want to swap it with a 66 model 396 and muncie 4 speed. My biggest concern is the clutch conversion. What options do I have? Any other suggestions will be wecomed as well.

[tfp1976]

The hard part will be having to custom fab the clutch linkage to make it work or you can convert it over to a hydraulic setup ive seen conversion kits avalible from some resoration parts companies the conversion kit would be the easiest way to go in my opinion

[v8sten]

i agree with tfp1976. either find a company that does hyd clutch conversion or fun a different type of tranny. like a nv4500. it'll hold up to the torque your engine will put out and you will have an overdrive. those style trucks came with those tranny's, get a peddle assembly out of another truck (itll be hyd) and plumb it in with a factory style bellhousing. itll be easier to run a braided stainless hose than to make clutch linkage, that may bind up.

[George C]

a local guy used a LT1 T56 mated to his 454. this is in his 454ss

[68 TT]

My first comment is that it will no longer be smog legal. If you don't have to pass a smog check no problem for you but if you want to sell it ever you may have a hard time trying to find someone who wants to buy a non-legal vehicle. I had to deal with this when I put a solid lifter 350 into my 91 RS Camaro.

The Muncie is not a good choice for a heavy truck and a built engine (they really aren't that strong in stock form, I have broken quite a few) plus it doesn't have any provision for a VSS to drive your speedometer. Find a newer 5-speed that came in an 88 to 98 truck and grab the whole setup to retrofit your truck.

The big block weighs close to 150 pounds more than a small block but with aluminum heads that drops by 75 pounds. Unfortunately aluminum heads for the big block are $2000+. You can occasionally find good used ones for less but most of the time they are being sold for a reason.

I loved the 396's I've had over the years in various trucks & cars but after having a 454 built properly in my truck I will never go back.

It weighs the same as the 396 and you get a bunch of extra torque for free.

Unless you all ready own the 396 it is not worth the effort to build one for transplanting into a newer vehicle. Find a 454 and start from there if you are set on doing a big block swap. You will have more piston options for the 454 as well for less money. The rest will cost you the same as a 396.

A better option is to do an LSx engine swap. A 6.0 liter engine with a cam swap can build just as much power as a 396 with stock passenger car cylinder heads. It will also weigh a whole lot less and could be made smog legal as well.

The big benefit is the LSx engine will be fuel injected and behave much better. EFI for a big block will cost you just as much as buying a complete LQ4 6.0 liter LSx engine.

There are high performance factory heads for the big block but they are rare, expensive and for the most part 40 years old. Again getting a good set and having them rebuilt will cost you just as much as buying a complete LQ4 6.0 liter LSx engine. The factory rectangular port heads will also kill low end torque due to the massive port volume.

Just a few things to think about before jumping into this swap. Don't get me wrong I love the 396 (I own and drag race a 396 powered 68 Camaro) but there are better options out there that will cost you less money and give you a better product in the end.