I was thinking about building a 434 stroker out of a 400ci sbc and was wondering what was involved with the setup.. what stroke crank should i look for also what rod length is best??? Will i run into any problems trying to run such a HUGH small block...Will the block have to be specialy machined ???

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69 Camaro RS, 355ci, 71 gm heads 74cc 1.72in 1.50ex,mild cam, Preformer rpm intake, edelbrock 600 carb, 350 turbo w/ shift kit 2500 stall, 12 bolt 4.56 posi..

You might be far better served by building a 406.A 434 will take at least a 4" stroke crank with issue's on block clearance.You probably will need a bowtie or aftermarket block,I dont think a stock block will work.custom balancing and piston's will be in order.I would consider a Bill Mitchell 427 shortblock,they can be had for around $4500 from doug herbert.You will spend way more then this from building from scratch.Did I mention you will need some high $ head's?

I built a small block 427, same as a 434, just a 4.125" bore vs a 4.155" bore.

I looked at all the options and felt that the tall-deck Rocket block/Dart Iron Eagle (Dart makes the Rocket Block for GM, and the Iron Eagle is identical except it is a wet sump block)was the best option. These blocks cost the same as the Motown blocks. World advertises their blocks saying that they don't have raised cam location or spread pan rails. In my opinion those features, found on the Rocket and Iron Eagle are significant benefits when building a monster block like this. The raised deck is a real benefit as well.

With a 4.0" stroke, you're going to have to do some significant clearancing on the block and pan rails with a stock block or a Motown. While it's not much of a problem with the Motown, the production GM blocks are not as beefy around the pan rails, and sometimes requires you to partially fill the water jackets with Hard Blok, since you'll likely have to grind into them.

With the spread pan rails of the Rocket/Iron Eagle, the pan rails do not have to be notched at all, and the bottom of the cylinder bores just need a small 1/4" notch. World makes it sound like having spread pan rails means you need an expensive oil pan, you can get aluminum pans for $250 from Moroso and real nice aluminum pans from Stef's for $400, pump/pickup included.

The raised cam location of the Rocket/Iron Eagle means you don't need a double undersized, small base circle cam. A Cloyes timing set for a raised cam block only costs about $90 and you can use a stcok timing cover. Additionally, you have the option of using Big Block sized cam bearings, or 50mm roller bearings (not really recommended for the street though). I use the BBC cam bearing in my SBC 427. This is a benefit because you can run a larger cam lobes. The cam I have(custom Comp mech roller 256/264, .690"/.650", 112LSA) wouldn't fit into a block with small block diameter cam bearing because the lobes have a larger radius. Rememeber, you're basically building a big block, in a small block package. Even the best small block heads are somewhat of a restriction for all of those cubes. I use a pair of Dart CNC ported 18* heads that flow 355/260cfm, and the engine could take more flow if I could get it, without hurting low end.

AS for the taller deck, this allows you to run longer rods. Needless to say, with a big 4.0" stroke, with a standard block, you hend up with a bad rod/stroke ratio. With the tall deck, I am running 6.125" rods which gives me a 1.53 rod/stroke ratio, slightly better than a 5.7" rodded 383 which has a 1.52 ratio. Since you're running a carb now, I assume you'll use a carb on the 434. Dart makes aluminum manifolds that fit the tall deck with out using spacers and only costs about $250, fitting both a 4150 and 4500 Dominator carb pattern.

If you decide to build one, you'll love it. Mine makes over 500+ ft lbs from 3000-7000 rpm, peaking at 580 ft lbs at 5100rpm, and 650 hp at 6700 rpm, dyno proven. All on straight 92 octane, idling at 850 rpm, and it runs all day at 190F.

Good luck!



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1982 Corvette
Tremec TKO
650hp/580tq SBC 427 (http://www.geocities.com/monty_williams)

Check out this Speed-O-Motive link for a 434 stroker kit: http://www.speedomotive.com/newpage3.htm.

However, I'd still go with the other post and build a 406. There has got to be some serious and expensive machine work involved with the 434 and I'm not sure you would gain that much other than expensive bragging rights. A well-built 406 with good heads will make 500+ HP.

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Scott
'69 400SB, Richmond 5-speed
www.geocities.com/sdenning1 (http://www.geocities.com/sdenning1)

Not to dump on Monte,but I did see your engine and very nice,But my buddy run's a 406 with 18* head's from petty racing,with cola 3.76 crank,je flattop's,6" billet rod's,1050 dominator,and lift around .700 in a bowtie block.On the dyno it made 740HP and 660lbs torque.In his 3600# camaro it run's 9.80's at 137 without a king's ransom. I'm not flaming you,but cube's are not all there is.

Glenn,

I don't take it as a flame, but I think you're comparing apples to oranges. He was asking about a 434, I assume for the street, and I was merely offering my experience with building a big small-block for the street. I am fully aware that max cubes are not all there is. Most importantly is flow and combustion efficiency. However, take two motors with proportional flow, and equal combustion efficiency, and the larger motor will make more power at equal rpms.

I could make another 50hp/50 ft lbs just by changing the manifold from my Hogan's to a Victor Jr. Add more cam and it'd make even more. Although my bottom end and valvetrain is rated at 8500rpm+, I have my rev limiter set at 7000, and selected the cam accordingly for that rpm range. Peak power at high rpms wasn't what I was trying to build. This is a 100% street engine that runs on pump gas, idles smoothly at 850rpm and doesn't ever overheat in any weather, plus it passed the Illinois emissions test in July.

I'd love to see the dyno sheet on that motor though, his CR, and what type of fuel he uses. Those are certainly impressive numbers, but I'm curious as to how good it would be on the street. I'll bet those Petty 18* heads are hogged out too. Mine are untouched, right outta the box. I could have mine ported and make more peak power, but I'd give up alot of low rpm torque, and that's what I want for a street engine.

If you want to talk about buddy's, one of mine races NSCA/NMRA in a '69 Camaro and runs high 6's at over 200 mph. Actually, he was the first ever in the series to run over 200mph at legal weight.


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1982 Corvette
Tremec TKO
650hp/580tq SBC 427 (http://www.geocities.com/monty_williams)



[This message has been edited by MontyW (edited 08-18-2001).]

Give stealy performance a call in east moline Il. 309-792-3333.Talk to steven and ask about Corey Fier's 18* 406,he dynoed it.I think he hit the light's at 8200 rpm.I was making a representation of what is possible with tried and true combination's of common cubic inch small block's.For the money involved,a 406 would be a perfect street motor.

Hey Monty, I two am building a 427, i plan two use an efi setup, trick flow heads ported to flow 230 cfm, comp cam 8-304-8 cam out of my 350 for now(dont have the specs handy), and ideas of what kind of hp and torque im looking at?

My two cents please.

What does anybody think about using the new 3.875" forged crank instead of the 4" one just because of a little less grinding in the main web area?? Seems like it would help and still you would end up w/ a healthy big engine.. 420 at .030" over and 426.4 at .060" over. pdq67

PS., I do know one thing that if I had the money ta play I would opt for a block that would bore 4.25" and build a 454 SB w/ the mini big block "splayed valve" heads or the SB2's just so the big sucker could breathe!! But this stuff is pricy.

Seems one has been made as big as 505.

Caddman,

230cfm is way to small for a 427, it'll run out of breath at low rpm. Stock small blocks are head restricted as is, when you add more cubic inche's, you definitely need more cfm. My heads flow 355cfm at max lift, but mid lift is the most telling. There are plenty of affordable aftermarket heads out there that flow 300+cfm at reasonable lifts while still having excellent low/mid lift flow.

Anyway, a rough estimate of hp potential is 2hp per cfm. My opinion is you'd be shorting the potential of your motor with 230cfm heads.

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1982 Corvette
Tremec TKO
650hp/580tq SBC 427 (http://www.geocities.com/monty_williams)