I've got a question for you guys, I've got a 1994 Camaro Z28 w/ LT1 A4 w/ 164k miles on it. I've got a 3.73 auburn posi w/ stock 10bolt rear axle. I'm debating on whether to sell off the LT1 and A4 and install my 406 sbc w/ powerglide transmission. Heres what the 406 has, 400 punched 30 w/ splayed 4 bolt main caps, 14.5:1 comp, Dart 2.08 1.60 heads w/ 64cc chamber heads, Victor JR race intake with Demon 850cfm carb, 1.6 ratio roller rockers, .510 .533 cam, forged crank and rods balanced w/ 5.7 rods. 1.76 planetary Powerglide trans w/ Hughes 4500 stall converter and ATI pro tree transbrake, the trans is built. I'm not looking for a grocery getter, I want something that hauls A$$. What do you all think??? The LT1 is stock except for the rear gears.

 

Well lets see, keep a stock LT1 or put in a "Built" 406", I wonder which will be faster??

For a track car I don't see any reason why not to step back 15 years with the technology. If you are going to drive it on the street then no.

 

I want to drive it a little on the street, just for fun, but its not gonna be something I'm going to drive on long trips etc. Just something to cruise around town with on occasion, but it will see a lot of track time.

 

I was also told the engine mounts on the LT1 will bolt up to a stock small block, I don't know if this is really true or not. I know the LS1's are different.

 

You should probably give this some more thought as a 14.5 to 1 motor (if that is truely the compression ratio of the motor) has no business being driven on the street as there is no pump gas available to allow the motor to stay alive and you probably don't intend on running racing fuel in a street car, just based on the cost per gallon. Additionally, the 10 bolt won't be long for this world either with a t-brake, 4500 converter and a 3.73 gears. Although, the above not withstanding, sounds like the small block is a nice combination.

 

Let a 4 bolt LT1 block. Put the 406 guts in the LT1 block. Keep the cam in the 260's on a 112+4 and ya can run 13/1 on pump gas with that BIG of a cam with the right tune

 

How much work would it take to get the 406 pistons and rods to fit in the LT1? What size are the valves of a stock LT1? Just trying to think of how hard it would be to swap everything over to the LT1 and how much modifying would be required if its possible. Thanks again.

 

You will need a rear main seal adapter and new pistons as the LT1 will not support a 4.125 bore. So in essence you would have 2 piece rear main seal 383 LT1.

What heads are on the 406??

If your going through all of this who cares what the stock valve sizes are?

 

406=4.030 bore x 4.00 stroke.

Use the heads that are on the old engine and have them converted. Use the intake too. If it's a carb get a elbow and hook it up like the factory.

 

The heads on the 406 are Dart 2.08 1.60's. I'm not sure what the LT1 heads are. Whats the stock bore of the LT1? So if I get this right, I use the stock LT1 block, heads, and intake, install the 406 pistons and rods, and have the car set up on dyno to run the new combination with the new cam?

 

Not quite a 406 is 4.155 bore x 3.750 stroke, a 4.030 bore x 4.00 stroke is a 408.

Youl'l need to get new pistons, the 406 pistons won't work since a 400 30 over is 4.155 and the lt1s stock bore is 4.000, even 60 over it is still only 4.060

 

Beat me to it

 

LT1 bore 4.0"
NO Use a 4 bolt main Lt1 block and swap the 406 guts into it. Have the 406 heads converted for reverse flow cooling(not a big deal), use the 406 intake and have it converted for EFI.
If ya use the LT1 heads the compression will go out of sight.

 

Ya can take a stock 400CID small block and bore .030 and have a 406

 

400 block has a bore of 4.125 stock hence a 30 over 400 is 4.155 bore

a 4.030 bore x 4.00 stroke as you claimed was a 408 is NOT 406 cubic inches, its 408 cubic inches and a 4.000 bore is from a 350 block, not a 400 block.