Me? I didn't offset anything!


I can tell Bret's gears are grinding away on this one.

The rods, did have a unique profile... they were made to Sonny's specs by GRP. Rod journals were 2.100". As far as that goes, everything inside this engine was made to Sonny's specs. The block came with no lifter bores and SAR machined them where they needed them to be. GM splayed heads get a lot of welding, a little comb. chmbr. move along with repositioning the spark plugs and valve guide centers..... valves were 2.28/1.680 using intersecting seats.

To give you an idea... this was (I believe) late 93'/early 94' so it's been some time. I do still have the block, intake crankshaft and cylinder heads.

Sonny is pretty secretive on what it takes to build one of these but he might be willing to throw it all out now that it's been a decade.

-Mindgame

 

Still turning man....

Never would want to do this, but I do want to know how to do it.

I was figuring that you start with a block without lifter bores and something wild and capable of supporting 500cubes in cylinder heads.

I gotta see that block and the rest of the parts one of these days.

Bret

 

Bret,

If you ever get the notion to build something like this let me know, Ill volunteer to supply the test car for ya, lol


-john

 

Just as a side note a production 400 block will handle a 434 ci stroker but it wouldnt live long as you have to grind excessivly into the pan rails to clear the crank/rods. Im in the process of building a 420 ci with a production block and even thats iffy.

 

lol........ I'd have a lot of volunteers for that one!

 

you dont need a tall deck block to achieve 434 cubic inches i say give a call to scott shafiroff. he'll build a forced induction small block short block for you as cheap as anybody. but if i was going to subject one to that kind of abuse i might start out with a 427 just for that extra little bit of cyl wall meat. dont get me wrong though it does take an aftermarket block to do it reliably with what you're talking about. i do imagine it takes a small base circle cam unless you go to a dart raised cam tall deck block. which is probably a good idea for you anyway so you can run a piston with any type of ch to it at all. those 434 and 427 cube small blocks have a very short piston in them as you can imagine with a 4" stroke and a 6" rod.

 

Yeah, there's a little bit of clearancing but "how much" will depend on the rod design.

Like I've mentioned before... way back when.... there were guys building 427+ ci small blocks for strip duty and they were runnng these engines for the whole season. There are tricks to making one live, but it is easy enough to build a street engine on an old block. Maybe not feasible when you crunch the numbers (machine work) but plenty possible.

-Mindgame

 

Since were on the subject here, We finished the machining on my 383 LT1 and its ready for assembly but I Have this 400 sb sitting here in my shop and ive been thinking about going down that road instead since the 383 was going to be with a single plane, carb, anyway. so i feel that it would make more sense to go with the 400, converted to 4bolt, and a nice set of 23* Dart Pro 1s, more cubes and more potential.. But what would you guys suggest as far as machining and rotating assembly, I would like to a do a stroker with it 420 maybe 434 but if that would take to much material out of it than ill pass. Or even a simple 406. The car will be mostly set up for the strip but will see occasional street time.


Thanks,
-john

 

Im building a 420 ci inch stroke 400 with the following parts: 30 over 400 block with Moroso Hard block to bottom of water pump holes, plugged steam holes and restricted deck water passages,moroso 4 bolt splayed main caps, C.A.T lower end cap girdle,and Eagle stroker kit with 14:1 compression ratio JE pistons.Im using a sollid roller specs:Lift .688/.674, duration @.050 is 272/ 285 and im also using the dart pro 1 23 degree heads except im using the cnc ported versions. We hope to make 700-750 n/a hp reliably and 900-950 with a 200 shot of nitrous on top.

 

Its sounding like a pretty solid setup, Im liking the 420... Were gona run eagle crank, H beams, Mahle pistons, I want to use Pro 1s as well, you said your going to run the CNC versions, how well did the flow out of the box??


Thanks,
-john

 

320 cfm @650 lift out of the box,they are supposed to be THE best flowing 23 degree head out there.

 

230s correct?


-john

 

I beleive so,they are sitting in the speed shop right now waiting for me to pick up. As soon as I get them I will be sure to post numbers.

 

Kind of off topic here but is the bolt pattern on the 400 the same as a LT1 becuase im planning on running a T56 and have been told that they are compatible.

thanks guys,
-john

 

Don't even think about a 434 on a production block if you're not willing to pay for a lighter rotating assembly. In that I'm saying that this is the place for those 45 lb and lighter crankshafts. Keep the rods and pistons light too... but not to an extreme.

There's a lot of prep work to making a production 400 handle lots of revs (been discussed in this forum before) but some of that can be skipped for a 6500 rpm street build. If you want more revs, why not just build something with a 3.875 stroke and larger bore. May be the best option at that point.

-Mindgame