Hey guys, So I have a 400sbc (511 4 bolt) & a TH350C I wonna drop in to an 86' irocz.. My problems are the I'm torn between building the 400sbc in to a mild 300-400hp street cruiser or boring it .30 over & building 406sbc to make 450-550hp to make a hot cruiser / wkend dragster.. ethier way I'm planing on putting all new parts on it & only reusing the block .. iv got about a $3000-5000. budget... So PLZ HELP!! I would really like to know your opinions on what you would do w/ my situation.. as far as parts/set-up options... or leads i can research.. thanks..

 

Thats going to depend on whatyou really want to do with the car.

300-400hp for a cruiser is fine...and you can keep rpm range low to match with a highway gear in the rear end so you can still get decent mileage out of the Th350 trans and a mild stall... 3 speeds and steep gear ratios arent real highway friendly.

450-500 hp build is gonna require more money, stronger parts, more gear/more stall and less cruising capability. ALOT more fun but abit moe maintenance and driveability concerns.

You can do what you want with the budget you have, but 450-550hp is definately going to take more of your budget because you will need better internals and heads.

 

First, it's 0.030" over, not 0.30" over. You can say "30 over", or ".030" over", or "30 mils over"; but ".30 over", that dog don't hunt (.30 does work for hunting, but not engines).

Now, why would you build a street cruiser on a stock bore, but a 450-550 HP hot cruiser/dragster at 0.030" over? That doesn't make any sense. If the cylinders need to be bored to the next size, they need to be bored to the next size regardless of how much HP you expect to get out of it. It could be argued that the stock bore would be more likely to take putting out 550 HP than the 0.030" over bore (more material to support the stress). Clean cylinder walls are important for either one.

Okay, I'll address your first comment last. A TH350 is fine for a hot street cruiser/weekend dragster, but would be annoying for a regular street cruiser (if you ever plan on driving over 40 MPH). The "C" doesn't help much for cruising, and I'd verify whether the lock-up version can be built the same way as a non-lock-up TH350 (personally, I don't know).

Certainly for a street car in the 450 HP range, a properly built TH700R-4 would easily handle the power, and be a much more tolerable cruiser. It could even be built to handle a 550 HP weekend warrior.

 

so 1st of all the ".30" was a typo.. so yea.. sry. & w/ out supercharging/ turbocharging & Nos I haven't really seen anyone who's built a 400sbc w/ 450-500hp on pump gas.. so if u know of anyone who has then maybe that'll be the route I take.
& 2nd My understanding from reading over multiple different forums on the TH350C is that w/ the corrected lock-up converter "It Should" give you similar MPG as a 700r4.. (which is what I'm replacing) & be able to hold up to more hp & torque..


I've decided that I'm gunna go w/ the 450-550hp crusier/wkend dragster ... If some one can tell me about 400sbc pushing 450-550hp otherwise im gunna go w/ the 406sbc. I wonna build a beast of a cruiser & still run on pump gas. I'm planning on going w/ all new components from the bottom up. including scat rotating assembly, flat top pistons & aluminium heads. I'v gotta decided on which components match up the best. If u have any suggestions let me know plz. I'm notta complete novice when it comes to engines & restoration but I am new to building a motor bottom 2 top on my own specs.. so any help you guys can give me I would greatly appreciate & welcome.. I want the pride of doing this build on my own ... instead of paying someone to do it..

 

IF the bore is good then you can run the 400. Else it will need cleaned up so bore it 30 over and go with a 406.

450 hp and 550hp is a HUGE difference in build, so decide where you want to be. Simple 450hp is like AFR 195's with a 224-230 deg cam. 500 is probably a 236-240 deg cam with either 195cc or 200-210cc heads that can flow. 550 is getting closer to a 210cc head with solid roller cam in the 250 deg duration range. It will peak in the 6400-6500 rpm range and deliver WELL over 450whp which is north of 525hp. Just some general ideas.

I'd go solid roller and 210-220 cc heads for a really strong weekend drag/cruiser. Victor type single plane. Compression near 11 to 1. That should fly

 

Copied this from one of Atilla's threads. It may give you some direction on top of what Orr has suggested.

Re: Atilla's best builds

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Carbureted 400
For those who can find a useable 400 small block, and can also
afford to top it well.

RPM TQ HP

2000 410 156
2200 418 175
2400 436 199
2600 460 230
2800 473 252
3000 474 271
3200 474 289
3400 476 308
3600 489 335
3800 501 363
4000 511 389
4200 517 413
4400 521 436
4600 524 459
4800 524 479
5000 517 492
5200 503 498
5400 495 509
5600 485 517
5800 476 526
6000 452 517
6200 441 521
6400 420 512

To copy this, start with a 400 with dished pistons.
This build used the following:
9.5:1 compression
coated-top pistons
COMP 12-000-8, 3017/3038, 110 cam on a small base circle
Dart Pro 1 180 cc heads
Dart dual plane air gap intake
1.5:1 roller rockers
Demon 650 carb
1/2" carb spacer
1.75" long tubes such as Hooker p.n. 2210-1HKR
note that this cam will never pass a tailpipe sniffer.

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Last edited by Atilla the Fun; 04-19-2010 at 06:51 PM.

 

actually, there is a ton of info on 406 builds. motor trend has a good article on a 406 build they did. HP is cool, but honestly, torque is what your lookin for. and a 406 can deliver tons of road ripping torque. and you can buy and build one for like 4 g's. i'v got a 406 block sitting in the garage just waiting and teasing me. i just need the cash for the valve train, heads and a suitable intake. the 406 is a strong breather due to the bore and stroke, so cam and intake are crutial.
just do a google search for small block 406, you'll see what i'm talkin about.
keeps us updated, i'm intrested in how yours turns out.

 

Honestly, I would do 10:1 with some Chevy heads that had a little elbow grease in them and a mild cam, and spend money to build the short block stout. Then full bolt on that thing (carb & intake/TPI setup, headers, exhaust, valvetrain) and it will rape on the street and be pretty reliable. But for a car, you will probably want something with overdrive as far as the trans goes. Bore it out as little as you have to in order to get the cylinder walls true. These 400's have thin walls, I would stay patient with overboring the thing more than needed to clean it up. It doesn't HAVE to be a 406 ya know.

On the OD note... I have a truck with a 400 SBC running 9:1 compression (different pistons and head gasket on the rebuild + true duals & an RV cam, everything else is stock replacement, it makes AMAZING torque) and a non-lockup TH350, even with 35" tires it is barely tolerable on the highway (although a bit of that is just the noise from true dual 40 series Flowmasters) at 3000 rpm CONSTANTLY at speed limit. I put the crappiest gas in it and it never detonates even driving up the mountain, but 3000 RPM everywhere is still a hefty gas bill. And at 65 mph it's LOUD, and I'm always the slowest one on the freeway in that thing... Always at 3k RPM's so I never want to go even 1 mph faster, LOL. It has 4.10's in it also. I'm sure you would need a 2.29 or 2.73 rear gear to even get to where I am on the freeway unless you run some monster tires too... LOL

Although I'm sure with a higher winding motor (mine is a truck motor, so it's built for idling a lot and pulling hard at low RPM) it won't be quite as nerve racking... It will still be unpleasant

 

Thanks for all of the advice guys!! 450hp 400sbc sounds nice but a 500+hp 406sbc keeps me up @ night just drooling @ the thought lol.. Right now the block is completely strip bare & is sitting in my garage because I'm leaving for a yr for the guard. I coated the cylinder walls & all of the machined surfaces in oil & cover up the block w/ plastic... Hopefully that doesn't screw me out of a block while i'm gone..

A 450hp 400sbc would make a mean little crusier but deep down I wonna build that 500+hp 406sbc. I'v gotta buddy w/ an '06 roush stag... & I wonna TEAR IT UP & LEAVE'EM CRYING!! lol

The only thing about building the 406sbc is that I fear the gas mpg will kill the fun in the building a cruiser.. an that's where the th350c comes in..

Does anyone know of a TH350C being put behind a 406sbc.. or sumthing similar & holding up & working w/ the lock-up converter working properly?? If so did the get better gas mpg then a basic TH350?? jw..

 

Dude, klm performance .. skipwhite performance... and summit for carb and intake thats what I did procomp heads, get the 210 ones... 6inch rods all forged from kmj and get the heads from skipwhite. Cam, intake and carb summit your wallet should cover it all.