Cris

I hope to build a big-inch small block and have started doing my homework. The motor will be used in a 1966 that will be driven on the street and club-raced at autocrosses. I am looking for good power from 2000 to 6500 with around 550 peak TQ and HP. I’d like to use a standard deck height block, and the motor must be pump-gas friendly. I was going down the path of the 434 (4.155 bore x 4.0 stroke) until World did the 454 (4.25 bore x 4.0 stroke). I’ve got lots of questions but let’s start with:

What do you guys think of the 454? Are the cylinder walls getting too thin for reliability? (SBC’s have a total of 4.4” between cylinders, leaving only .15” in the 454.)

I have found great prices for short blocks from Dyno-Flo and Ohio Crankshaft. (Dyno-Flo is all over E-bay and racingjunk.com with their 434 kits.) These two companies are coming in around $3600 for an assembled short block. (I will order an unassembled kit.) Has anyone dealt with these companies? I don’t really want to deal with an unknown vendor. Part quality is Dart or World blocks, Eagle cranks and rods (Ohio Crankshaft does their own cranks), and JE pistons.

MotorHead

If it was me ( and it probably will be sooner or later ) I wouild get a standard bore aftermarket block and add 4 in. crank making it 427ci then you can rebuild/rebore after that to 434 or whatever, I think a 454ci ( I am not sure about this so check with the vendors ) is the limit therfore if you nick a cylinder wall it's a boat anchor.

gkull

If i had it to do over again I would not use a standard height deck block. The raised cam is such a good idea. The ability to use longer rods....... many advantages to the taller deck.

When my 427 was being balanced. The shop was doing a tall deck witha 4.155 bore and 4.125 stroker crank. I can't remember if it was 441 ci or 446 ci. It was a 600 some HP motor going in a Camero

With 427 - 472 ci small blocks your going to have a problem putting the power to the ground for auto - X

2manyfuncars

If you are going to do it yourself, go with the tall deck block with the wider pan rails. Less grinding and cam clearance grief. But if you are only looking for 550 hp, you don't need the 434 or 454. If you are set on a standard deck block, a 400 or 415 would do the trick and is easier to deal with. Be careful of really cheap package deals and non-brand name components.

Good luck

gkull

2manyfuncars - Both the Motown and Dart standard deck blocks require no grinding even with 4.125 stroker cranks. They are so superior to stock blocks that you would never use a stock block again.

The oil pan from a stock block will not fit the aftermarket blocks. I have a Motown 7 quart steel with lots of traps and baffles. It's not as good as my Morroso 8 quart road race pan which came with adjustable screen type crank strippers.

IMO - the additional TQ of the 4 inch or longer strokes makes them a cut above any 400 - 421 ci 3.75 or 3.875 crank.

Cris - another thing to look at when shopping for these motors the crank main journal size. I have the 350 size mains. Weight and main bearing speed is a consideration on any mid 500 hp good time motor. Try to keep your compression up. I set mine up with an intended 7000 rpm red line with a solid roller.

Cris

Thanks guys. I’ve been reluctant to go with a tall deck block because of the added expenses. I’ll also have to modify my headers/exhaust to accommodate the .3” increase in deck height. You may laugh at this but I’m hoping to build the motor for around $7K. This is my first build from the ground up, so I want to keep any mistakes from costing me too much. I’m helping (learning) a friend screw together his 454 SBC tall deck right now (4.125” bore x 4.25” stroke), he’s got over $20K in his motor.

MotorHead: I think you’re right about the 454, if you nick a cylinder wall, you might be in for a new block. Maybe not a great choice considering I’m just an amateur at this stuff.

gkull: I'm with you on the 350 mains. I assume the 400 mains are stronger, but I'm not building a killer motor and I can always use the free HP. I'd love to use a solid roller cam, but do you think that's a good choice for a street motor?

2Manyfuncars: I'm opting for displacement cause I'd like to build a mild motor in the 550HP range. I looked hard at the 406's (they're cheap!) but felt anything much above 500HP loses street manners.

I’d like to get a read on Dyno-Flo or Ohio Crankshaft. A quick way to blow my budget is getting crappy parts that need another $2K of machine work.

gkull

The material or how that the crank is made determines the maximum hp potential that a crank shaft has. Not the diameter of the main journal. Crank like my 3.750 are rated at 850 hp and they seem to run fine under TT and 1200 hp.

All motors 383 ci through 454 ci will make the same amount of HP if every thing else is the same. So if you have Motown 220 heads with 2.12/1.60 valves flowing 315 cfm @.600 lift and a h-roller cam of 242/248 112 lc 11:1 compression, single plane intake with 750 cfm. Your going to end up with just under 600 hp in all the motors. Your only real change is about a spread of 80 foot pounds of TQ and the HP peak will probably also be an 800 rpm spread.

Cris

gkull:

I have several models on DD2000 (406 through 454ci) and they pretty much predict what you are saying. I'm after the larger displacement to keep revs down, and have good torque and throttle response down at 2000 RPM. I want this to be comfortable on the street. A 406 with 220cc heads won't even wake up until 3000RPM. Peak power is probably close to 7000RPM.

gkull

Funny that you should say that. I have a 700R4 type tranny with a switch for lockup in fourth gear only. I have a 383 ci with Dart Pro1 227 cc heads with 306 cfm of flow @.600 a SR cam 238/246@.050 with .620/.620 lift.

I can put my car in lockup fourth gear at 2000 rpm then floor the gas petal and out accelerate most of the cars on the road. Your right, motors like mine really run when you get the rpm even higher, but the over 500 foot pounds of TQ for 3500 rpm is a broad power courve

It's the cam that determines how a car runs at lower rpm not a few cc's in just a little part of the whole intake tract which actually includes the volume of the whole intake manifold plenum port.

comp

454

MotorHead

I think you might be suprised if you built a 406ci. First I have a solid roller with close to 250 deg duration @ 0.050. I have 215cc ( actually cc's 219cc ) Victor Jr. heads. and 11:1 CR. When I drive around town the motor behaves like a "normal" motor and I can cruise at 1800RPM with 3.08 rear end in fourth gear, until you downshift hit the gas, then it will break the 295's loose at 50mph.

Here is a chassis dyno printout and keep in mind I shut it down at 5000 RPM's because I didn't want to have any trouble with the tranny I just put in. I was not even going to dyno it after blowing my original Super T10 the first day I put the motor in. The motor will make peak power with this cam at about 6300 RPM and as soon as I put the new TKO 600 I am getting it dyno tuned and taking it to the track. As you can see there is plenty of torque at 2000RPM. I might lose a little when I put the new 1 7/8 in Hooker sidepipes on.

I went into detail here becasue I think somehow you got the wrong info on a 406ci and I think if you build a 406ci you will love it and you will save a ton of money

Russ Bellinis

You can't take a stock block out to 454 ci without striking water. The Motown block will easily go that big because the cylinder walls are thicker than the stock block. In particular, the sides of the cylinders in the lifter valley are humped to give thicker walls, whereas the stock sb has the sides flat in the lifter valley area. I think the biggest problem financially with going 454 is that the big bore pistons and cranks tend to be high dollar forgings. If your not going nitrous, a blower, or high sustained rpm levels, a cast crank and hyper pistons will be fine. I just don't know if anything is available for that big a small block motor other than forgings.

stinky

Cris, I purchased my 540ci shortblock from Dyno-Flo, great prices, quick delivery. Same manuf., Eagle, JE/SRP, Merlin III, King bearings. Only problem I ran into was they didn't ship the rings and sent wrong main bearing kit. They rectified the problem but stay on them if you have this error. Mike

Cris

gkull, MotorHead: Sorry didn't mean to malign the 383 or 406. MotorHead, those are awesome numbers on the chasis dyno. I was all set to go with the 406, then I noticed the 434 and 454 kits so cheap. Dyno-Flo had a 434 Motown based short block at $3400.

Russ: The only block I've seen out at the 4.25 bore is the Motown. Even Dart won't commit to that bore size. You're right about the cast stuff. I called around and nobody makes those parts cast (I sorta liked the idea of using Hypereutectic pistons). Though, the Eagle and Scat 4340 forged cranks are getting so cheap they're affordable for tight wads like me. I know its not a Callies or Lunati, but I'm not John Force.

Mike: Many thanks for weighing in on Dyno-Flo. Their ads imply they are good guys and racers, and they have been in business awhile. How was the machining quality? Have you fired up the motor?

Comp: I hear you. My brother, a drag racer, just keeps repeating there's no replacement for displacement.

2manyfuncars

Cris,

A 66 with massive torque is going to be challenge to autocross unless you run big sticky race rubber. I found that with my 65 (before I took it off the road 7 yrs ago) it was also nice to have more rpms to play with to save a gear change. I also ran in one gear higher than needed sometimes just to make it easier to drive and I only had a roller cam 355 with track I's. There will also be issues with the tires hooking up especially if you don't have flares and 315's or something. It's a fun problem though.

Good luck

Cris

2manyfuncars:

I can't believe I haven't run into you around the Bay Area. I run the WSCC autocross series and am the competition director for Santa Clara Corvettes.

I run my '66 in the street prepared class with 245-50-16 Bridgestone RE-730's, a pretty hard tire. Even with a 350-350, traction is an issue. I'm not flared yet but it is in my future. This is a downward spiral....... bigger motor, bigger tires, beef up drive-line, then repeat as necessary.

2manyfuncars

Cris,

I have not been doing any auto-x for years since my 65 has been in pieces in the garage. I do run at road race tracks with my blue 1990 C4. My wife has been disappointed that the 65 has been off the road so long - it's her favorite car. I had 255 -17's on it...

gkull

2manyfuncars - Do you compete at thunder hill in your 90? I've got an incar video from there where a mid year 65 or 66 convertable with a 427ci just leaves a modded C-5 out of every turn.

That where the extra ci torq monsters really shine. The 427 - 446 ci small blocks would be the way to go. Bill Mitchell Hard core racing does sell a complete aluminum 454 SBC with something like 575 hp and a 2 year 24,000 warranty. 420 pounds.

2manyfuncars

Gkull,
I do Thunderhill a bit. It's about 3 1/2 hrs from me, but it's a fun track. Laguna is just over an hour. I'm hoping with the new motor in my c4 to show some c5 guys what serious torque does for you...

I wish the 65 handled like the c4's or c5's... They are way more cool to look at. I also have a 70 Mach I that has a heavily modified chassis and a mainly stock 351C motor that I take to the track too, but it's outclassed by the c4.

gkull

I saw this statement about the .3 inches and header mods. If your truely worried about this small amount your limiting yourself as to what heads you can buy also.

My Dart Pro1 heads has .600 raised exhaust ports. That's partialy why they have the big flow numbers. what you and others don't understand is your really not .300 taller or in my case .600 taller. Look at the V-8 motor. Because of the angle the taller block is maybe .150 taller and .150 outboard. Which is nothing.