Just curious, but is it possible (or reasonable) to build a 427ci small block? Any one out there done it? What would it take, bore, stroke, type block, etc etc?

tom...

 

Very good motor. Can be done with a 400 block but for serious Hp I would go with the World or Dart block. Has been done many times and can build some high HP with this motor. If I was going to do it over this would be my choice. It is not going to be cheap but HP never is. Monty I'm sure will have more to say on this as he has one.

 

I have one "D :smash: :smash:
actually I don't, it's bigger! 434" :eek:

Cost was about $8k three years ago. Had a professional race engine builder put my parts together :cool:
When he was done, it was broken in and Dynoed, ready to beat the hell out of!

I knd of put a crappy cam in it tho, only got 460 hp out of it, someday I'll re-cam it and get closer to 600 :)
Check the sig...

 

Mine's a 418. A big inch small block seems to be one of the best kept hotrodding secrets out there...

External dimensions: Identical to a more typical (e.g., 350) small block
Torque: More like a big block!

Sounds like having your cake and eating it too. Add to that the fact that they can be built for less than you'd think, and your face starts to look like: :D

For a bit of drool factor, check this: http://www.speedomotive.com/425%20H....T%20MASTER.htm

-Noel


[Modified by Noel Carboni, 7:11 PM 2/21/2002]

 

Like Noel, I have some experience with a big-cube SBC (415). I loved the torque. Correctly done they are awesome engines.

However I'm going with a 406 now because of an unfortunate Kaboom! brought about by complete ignorance of the top ring gaps required to successfully run hypereutectic pistons several months ago.

Wanna buy a cast stroker crank? 3.832" coupled with a 4.155" bore in a 400 block will give you 415-point-something inches of displacement. A very, very light polish on the journals and you'll be ready ro rock and roll...

 

With a standard deminsion small block you can go up to 440 CI 4.185 bore X 4.0 stroke.

If you use a Olds Rocket block you can get a small block up to 467 CI 4.185 bore X 4.250 stroke. You can get this big with a rocket block because they have widend pan rails and a raise cam bore.

I built a couple of 461 CI in a rocket block but didn't really like them. They made 760+ HP but because the crank gets heavy the motor is not as responsive as a little shorter stoke motor with a lightweight crank.

A 427 small block combination is usually 4.125 bore X 4.0 stroke.

Any of these combinations get pretty pricey!

 

Hey Dude, Would you run that by me again--- you know, the part about top ring gap [not the kaboom cause I don't like that noise] thanks, Rick
:eek: :eek: :eek: :eek: :seeya

 

El Duderino,

So would that crank work well with my 268h cam in a 400 block? ;) And will it pass smog? :)
-terry

 

faster69, hypereutectic pistons like a wider top ring gap than that typically used on other types of pistons. The Kaboom! came about after I cracked a hypereutectic and replaced it using the wrong spec on the top ring. I had it within spec for a 400, but about .007-.010" or so too tight for the hypers. Check the Keith Black site and search around. You'll eventually find the scoop buried in all that info. Anyhow, everything was great for a while--the car ran a best-ever 12.31 at 110 with iron heads and 3.08 gears. 60-foot times were pretty consistent at 1.74 with ET Streets. It was SWEET. But then I made that fateful pass at Carlsbad on April 22, 2001. I went through the traps and Kaboom!. The ring ends butted. This tore the top of the hypereutectic piston right off and locked it at TDC. The rest of the piston shattered into a gazillion little pieces while the now-pistonless No. 5 rod and wrist pin continued to go up and down at 4,500 RPM. This made a Big Hole and lots of white smoke.

Therein lies the genesis of the 406--a little engine I like to call "Project Problem Child."

terryrudy, I was successful in getting the 415 to pass Cali. smog at a test-only station with a somewhat larger hydraulic cam than the 268H. The one that was in the 415 was a Lunati with 225 degrees duration at .050" and something in the neighborhood of .460" lift or something. Technically this was a very mild cam for an engine of that displacement. It idled like a sewing machine and pulled about 21" of vacuum at idle in Park. Of course, I also had all the smog equipment in place and functioning, a good tuneup (with initial timing at 8 degees) and all the rest of the stock equipment such as AIR pumps, closed air cleaner, yadda, yadda. My ONLY concern was whether the lab-coated technician would try and call me on the dual exhausts (But I was well prepared for that :D ) or the externally balanced damper.

Your mileage, of course, may vary.

BTW, if you're really interested in that crank, LMK and I'll see about having it mag checked for you on my dime. It WILL require some work on the journals since the engine was still turning when it blew up and metal fragments got into the oiling system. Nothing major. You could PROBABLY still use standard bearings. I could have that checked for you, too, or you could do it up there at the machinist of your choice. If it doesn't pass muster get it back to me and I'll give you back your $$. BTW, the 415 is a strange hybrid in that it uses 5.7" rods from a 327. In fact, I believe this crank started life as a piece from a 327. The boys at Speedomotive welded up the rod journals and gave it an offset grind to get the Big Stroke. And, to give you an idea of the compression height of the pistons you'd be looking at, I was running Federal Mogul H615P-30s. Specs are on the WWW, I believe.

Such a deal for you, huh?



[Modified by The Dude, 5:24 PM 2/21/2002]

 

If you got the $$$, you can always do a Monty:
http://www.montygwilliams.com/

He's throwing twin turbo's on it now, but you can go to the engine part of his homepage, print it out and go to an engine builder and have a 650 HP sbc 427 built to his specs. I think he put about $20k into it :eek:

 

I've always been a BB guy but I've gone for a couple of rides in Keiths (427V8) big cube small block and it's a powerhouse, lord help the neighbors after the next cam swap!!
I'm more impressed with the setup everytime I get a ride.


Greg