I recently picked up a small block 400 that has already been bored .30 over , but needs to be gone through again( #5 piston broke, but no wall damage). I have heard of guys putting together 434ci. small blocks with huge amounts of power, what does it take? I am assuming differant rods and bore size... Can anyone fill me on on the details? Also, it has #333882 heads, are they any good? Thanks in advance.

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1991 Camaro RS/Z28,polished TPI, 355ci. Sportsman 11 heads, LT-4 Hot cam,Pete Jackson gear drive, on,and on, and on... 13.4 @ 104.8 with a 2:77 rear, no traction, no tuning, no practice. Car is pictured in Chevy High Performance magazine, June 2000 issue.
http://www.geocities.com/jasonsz28us/INDEX.htm


1997 GMC Yukon, 4 wheel drive, leather, loaded, Gibson exhaust, K&N intake, Boston pro series speakers..... That's it so far.

1969 Camaro,12 point cage, total project right now, I am planning an LS1 - T56 - and a Vette independent rear. Pro Touring crowd, look out! 8^)

 

I can't lend Much to the big Cube question, other than A deep pocketbook.

But As for the heads, They are Decent smog heads. Stock On late 70's 350's and 400's.

With a lot of work, they can be made to Flow Quite well, For a Smog head



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60 Ranchero - Project ( Money Hole )
85 Sport Coupe LG4 - Daily Driver 15.26 @ 87.0
Reader's ride -> My Ride

Just another Hot Rod kid, or thats what they all tell me.
Livin' the Stereotype

 

Basically, the 434 is a 400 block over-bored .030” (4.155”) with a 4.00” stroke crank. The block may need some clearance work. Definitely a small base circle cam will be needed to clear the increased stroke. You’ll have to use a lot of custom parts for use with a 434.
If you’re thinking of using 882 heads on that motor, don’t bother. 882’s are lightweight smog heads, have 76cc chambers and were known for cracking underneath the valve spring pocket. Deck thickness is already thin and having them rebuilt and surfaced will only make the deck even thinner. Even fully ported and larger valves, performance on those heads is marginal. The cost of getting those heads rebuilt and fully ported isn’t even worth it.
Definitely large flowing heads are going to be needed with a 434. Heads like the Brodix Track 1’s, AFR 220 or the Pro Action 220’s are what I would go with.


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N/A 406, TPIS Miniram, 58mm TB, 30lbs injectors, Custom Ground Elgin Cam, Ported TFS heads, SLP 1-3/4", & DFI computer.
11.70@117mph

 

The rod ratio on a SB with anything longer than a 3.75 inch stroke becomes really marginal. You end up with having to compress the rings into a compression height of less than 1.2 inch. This requires a support for the oil control ring because the wristpin is so high. Not really worth it in my opinion. You can make a 400 have almost the same torque and it should be more reliable (have longer life)

I suggest getting an aftermarket head. Even if you spend 40+ hours on a factory head, it will not flow with some of the current aftermarket heads out of the box. For 800-1000 bucks you can get a good cast iron head that will flow the right amount of air for a 400. Aluminum heads will run from 1200-1600, but again, are worth the money. You can quickly ring up 1200 bucks in a shortblock and those parts don't make HP, the heads do.

[This message has been edited by jcb999 (edited May 22, 2001).]

 

The best way to 434 is the new World Products Motown shortblock. The block itself is ~$1600, haven't heard what the shortblock will run.

A stock 400 block is best left at 406 max. Get 5.7 rods and matching pistons, but stroking it beyond 3.75" is asking for trouble.

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R4. 2.93 limited slip. Cat-back from '91 GTA, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LG4 w/'87 LB9 block, ZZ3 cam and intake, World 305 heads, Hooker headers & y-pipe, 3" Catco cat & 3" cat-back).
57 Bel Air, my 1st car. 0.030 over 396, 9.7 CR forged TRWs, Weiand Action+, Edelbrock 1901 Q-Jet, GK 270 cam, Magnum rockers, Jacobs Omnipack, 1-3/4" Hedders & 3" Warlock header mufflers, TH400 w/TCI Sat Night Special conv & Trans-Scat shift kit, 3.08 8.2" 10-bolt w/Powertrax, AMSOIL syn lubes bumper-to-bumper. Best 15.1/95.5 @ 5800' Bandimere.

 

I was considering this awhile back and was told that the stock 400 block cannto be clearnced enough for the 4in stroke. you run into water passages. i would stick with the 406. check this out
www.allchevyengines.com

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89 RS (supposed 350) TBI auto

 

I am running a GM tall-deck Bow-Tie small-block. My engine builder is very familiar with the 434" combo. He told me there is a lot of side-thrust placed on the cylinder walls, and the engine will wear much faster. He said they make great drag-only engines if you plan on tearing the motor down a lot. I would suggest an aftermarket block such as a Bow-Tie or Dart Iron Eagle that can handle more cylinder abuse.

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1989 T/A, 400" CNC Bow-Tie tall-deck, JE 8.5:1 pistons, Scat H-beam 6" rods, Scat 4340 crank, Crower roller cam, AFR heads, Tiffin Racing sheetmetal intake, Holley 75mm t/b, DFI, variable injector controller, 72# inj., S/X dual-pump fuel system, Hahn Racecraft T76 single turbosystem, NOS 150-hp dry fogger, TH400 w/GV overdrive, Dana 44 w/Detroit Locker and 3.70's, Baer Track brakes, Simmons FR 18X9 and 18X10 wheels, P265 and P285/35ZR18 Nittos, Spohn suspension, Eibach racing springs w/adjustable-height collars, billet camber/caster plates, KYB AGX adjustable shocks/struts, Corbeau Targa RS seats, TeamTech 5-point harnesses, Sparco steering wheel, MacEwen white gauge overlays, Phantom gauges/tach, B&M Pro Stick w/carbon-fiber ****, REAL carbon-fiber dash/console kit (don't ask), S&W 8-point rollbar, Lonza aluminum pedal covers, Pioneer/Boston Acoustics stereo system, filled side markers, Audi fender marker lights, IMSA-style cowl hood (don't ask), custom medium Intense Blue pearl paint, tinted glass. Whew!

Best ET w/383" S-trim: 10.796 @ 125.8 mph
Best ET w/400" turbo, nitrous: Summer 2001

Member of Midwest F-Body Association www.mfba.org

 

I built one not too long ago, although I didn't do the block clearance work; we used an off-the-shelf Comp hyd roller and a stock block. It had an Eagle forged crank and Eagle 6" H-beam rods with screws instead of nuts. I don't think it tool very much grinding at all.

Don't try to do it with stock rods, or any other ones that use normal rod bolts and nuts.

Those heads are trash, mid-70s smog garbage, one of the main reason that 350s were rated at only 165-180 HP in those years. Throw them in the cast iron pile and get something real. They are inadequate even for a moderately warmed-up 350, let alone an engine 25% bigger than that, that's supposed to run good. Remember, the bigger the motor, the more flow is required in the induction system at any given RPM.

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"So many Mustangs, so little time..."
ICON Motorsports

[This message has been edited by RB83L69 (edited May 24, 2001).]

 

I just completed an SBC 434, it made 650hp@6800rpm and 580ft lbs at 5100rpm, over 500 ft lbs from 3000rpm thru 6700rpm. This is dyno proven horsepower not Internet BS.

I used the Dart Iron Eagle "Rocket Block" with the 9.325" deck height, Big Block cam bearings, and 4 stud splayed steel 400SBC mains. Even with the Crower 4.0" stroke Ultralight crank, I was able to run a 1.53 rod/stoke ratio with 6.125" Crower Stroker Billet rods, and a compression height of 1.17". For comparison purposes, the widely used 5.7" rod 383 has a R/S ratio of 1.52, so my R/S is slightly better. When we dynoed it, on several occasions we overshot the dyno it accelerated so quickly. The guys at Fast Times Motorworks, who are very popular among the NMCA/NSCA/NMRA racers, commented that it was "very frisky". The JE pistons are made for NO2 and forced induction applications, so strength was not compromised

The heads are the key. I used Dart CNC 18* heads which flow benched at 355/260. That's where the power is. We tested several different cams, and even with the smallest one, a 242/254 mech roller, it made 622hp/565 ft lbs.

While I can't say it was the cheapest motor to build, it made awesome power, and should be as reliable as any other high-performance street motor.

By the way, this was all on 92 octane, right out of the pump.



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1982 Corvette Tremec TKO
<A HREF="http://www.geocities.com/monty_williams/434specifications.html" TARGET=_blank>SBC 434 700hp/600tq
</A>

 

Yeah, so what Monty...that's only like maybe 525 HP at the rear wheels

 

I will admit that 650hp is very impressive. However, I would not really expect this motor to be reliable. This is really not a street motor. Anything that makes peak hp at 6800 is not intended for the street. Sounds like you have addresed many of the issues others overlook when building strokers.

However, if you have all that money in it, you will need to maintain it to make it last. That includes replacing valve springs and possibly freshing the motor at no more than every two years.

 

I would be foolish if I said that it was going into a daily driver, but I only use the car on nice weekends, maybe 4000 miles per year. The only thing that would limit it's reliability is the valvesprings as you pointed out. I used PSI springs, which are considered the best among the pro's, and I'm running lighter springs than you'd think, 185/475 lbs. But the .690/.650 lift will limit their lifespan. I would assume they'll last at least 2 years or so. Other than that, the rest of the motor was built "overkill" to ensure relaibility and durability. The rotating assembly is good for over 10,000rpm and easily over 1000hp. The valvetrain is the same that all the racers use, Jesel. And the Rocket Block is designed and built for racing applications that make much more power than I am. When you consider that it'll be operated in the 2000-4500 rpm range the majority of the time, the motor will not be stressed.

"Streetable" is a relative term I suppose. To me, it means that it will run on pump gas, will not overheat, and idles smoothly. So far, my engine does that. We have it idling at 850rpm, and that's without using an IAC. Since this is going into a street car, the 6800 rpm HP peak point doesn't mean much. I will rarely have the opportunity to rev it that high, but consider that the motor makes over 500+hp at 4500rpm, and 600+hp at 5500rpm. Those are certainly streetable rpm ranges, especially with the 3.27 first gear in the TKO. I know alot of people, especially guys that are running MiniRams who make peak power in the 6500 rpm range, 6800 really isn't that much different, especially when you consider my torque curve.

Personaly, I like to tinker with cars and motors, I think that's almost as much fun as driving them. I had a nice 450hp SuperRam DFI 383 in my car prior to the 434. I had it in there for 2 years, put maybe 5000 miles on it and got bored with it. I recently sold it to a friend. I wouldn't be surprised if I pulled this motor in in 2 years and built something else. Actually, I've already been thinking about swapping in some 8:1 CR pistons and a new cam, and adding a pair of intercooled turbo's on it. I think that's the next step.

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1982 Corvette Tremec TKO
<A HREF="http://www.geocities.com/monty_williams/434specifications.html" TARGET=_blank>SBC 434 700hp/600tq
</A>

[This message has been edited by Monty (edited May 25, 2001).]

 

It sounds like your are pretty realistic about the application of such a combination.

Under most cases, a 6800 hp peak would require you to buzz it to 7300 to really be at the right rpm for the next gear. But with the torque and gear spacing a tremec has, your in pretty good shape.. traction will be
your biggest problem.

Care to share some of your cam timing info with us? (or me via e-mail?). Like what were some of the different cams you tried and results?

Have you done anything to the IRS of that vette? I think they are pretty stressed at 400 hp. I know someone that had to grind out the inside of the IRS and put 12bolt guts in it.



[This message has been edited by jcb999 (edited May 25, 2001).]

 

I don't mind sharing any of the info I learned form building this motor. When I fist starting researching and planning for it, I found that there really wasn'y much info on building one, and alot of people were tight lipped about details. I'm not like that, that's why I made the effort to detail it all on my webpage.

The first set of cams we tried were relaively small. They are all Comp mechanical rollers. I ordered 3 custom cams using Comps Xtreme Energy Street Roller cam lobes. I started with a 242/254, .646"/.621"; a 248/248, .653"/.614"; and a 248/254, .653"/.621". All were on 112 LSA's and all were initially installed straight up on 112 ICA's.

Surprisingly, at least to me, was that the results were pretty similar for all of those cams.

The results ranged from:

The 242/254 cam made a best of 607hp @ 6400rpm and 548ft lbs @ 5000rpm. It made a nice flat 500+ ft lbs from 4000 thru 6400 rpm and over 500hp from 4800 thru 6800 rpm.

The 248/248 cam made a best of 618hp @ 6600rpm and 554 ft lbs @ 5000rpm. It made similar torque and power curves at the first cam.

The 248/254 cam made a best of 622hp @ 6700rpm and 562 ft lbs @ 5000rpm. The torque curves were pretty similar, except they fell off about 200rpm sooner.

Since I have a Jesel external belt drive we did try adjusting the cam timing a little. Of course advancing it made a small increase (10 ft lbs or so) at peak, but sacrificed a similar amount of HP at peak.

After the first day on the dyno and tuning the SpeedPro, we thought that it wanted more cam. Plus I was hoping to get 700hp/600 tq. So I orderd a new cam, a custom Comp Mech roller using their Hi-Torque .406" lobes. We used a 256/264, .690"/.650", 112LSA, installed on a 110 ICA. We spent the next friday with it on the dyno again and made a best of 650hp @ 6800 rpm and 580 ft lbs at 5000 rpm. I fell short of my 700/600 goal, and think that it could use a little more duraiton, but I'm pretty satified with how it cam out. In all honesty, traction and drivetrain durability is the question now. In my opinion 500hp/500 ft lbs is alot for a street car with street tires, anything more is just for the ego and bench racing.

I am still running the IRS. I have upgraded some of the the components. A company called Tom's Differentials amkes some nice stuff for the Corvette IRS. I have upgraded to their forged spindles and yokes. The driveshaft and halfshafts are from Denny's Drivetrain. I had to either shorten or get a new driveshaft made when I swapped out the 700R4 for the Tremec TKO. So I just had Denny's make a new driveshaft. They guarantee that you cant break or twist their stuff, and with street tires, the tires spin before the drivetrain can get too loaded up.

The differential internals are Dana44 stuff. I rebuilt it a couple of years ago with new bearings, seals, shims and clutch pack and it has held up pretty well. I'm hoping with some sane driving, no clutch fump jack-rabbit starts, and staying with some sticky road race tires will allow it to stay together. I know of another guy on the Corvetteforum.com board who races an 82 in NHRA racing regularly, and runs mid 11's in Denver. At lower elevations he could probably run low 11's/high 10's. He runs a stock Corvette IRS and doesn't seem to have a problem.

There's another guy on the Corvetteforum who is wrapping up a Merlin 540 with a Quad Rotor Whipple Charger that should make around 1500-1800hp. He plans to drive it on the street exclusively and he's using modified Corvette IRS from Tom's and Denny's. I think he'll smash his diff to pieces...


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1982 Corvette Tremec TKO
<A HREF="http://www.geocities.com/monty_williams/434specifications.html" TARGET=_blank>SBC 434 700hp/600tq
</A>

 

thanks for the time monty. Yea,, i have close to 500/500 with about 3150 lbs and it's pretty speedy through the gears.. I cant imagine much more than that.

You and the 89T/A guy up there must be some of those chicago area folks with the speedy cars

[This message has been edited by jcb999 (edited May 25, 2001).]