Richieg1g

Anyone tried a 427 SBC recently? I am thinking of this with AFR heads and a roller cam for the street and some track days. Pro's and con's?

(400 block with a 4" stroker crank = 427 ci.)

VETDRMS

GKULL should chime in here soon.

45ACP

gkull just put one in his '79. If I remember correctly, he is figuring on an output of about 600hp out of that thing. He was going to take a long-ish trip with it last week to break it in....

http://forums.corvetteforum.com/show....php?t=1049804

WayneLBurnham

The current temporary mill is a 413. Now my engine builder made several mistakes, one serious, several annoying and one we hopefully will never see the results of since I intend to change it.

He did do decent work on the heads though and the machining I witnessed was first rate as far as tolerances (some are just better at machining than putting together packages - and better at ripping me off...)

Anyhow, for whatever it's worth, I originally went in with this idea and he strongly advised me against any stroker on factory siamesed sbc's - even a little 1/8" one (3.875".) He said (and I looked around at the time and found some supporting commentary) that while the 400 blocks really didn't have too many problems as long as you didn't cook them too much, increasing the stroke experientially resulted in a much greater number of "egg-shaped" bores. He had no problem with strokers of any silliness on 350's or on BB's, but not on the siamesed 400 blocks.

The fifth block we got was the first one that was usable, but only then if we bored it to a maximum (and thus non-rebuildable) 0.060" over. This didn't bother me, both as I had the silly idea this nearly $10K would a)run problem free for several hundred thousand miles and b)yield 500 hp and 550 ft lbs. - and, most importantly, that it was really only a temporary engine anyhow. A nice new casting aluminum block from World or Donovan or several others in the 400 set up is less than $2K so I could always use my high end parts on a new, better engineered, "boutique block" anyhow.

Up to you - I don't honestly know. The idea that moving the slugs through a bigger hunk of those siamesed and thinner bores putting more stress on them made some sense. Then again, I no longer take a single thing he represented as more than a "what I've seen" guess.

-----

Oh, and the real summary - for the outrageous amount the stupid temporary small block cost to have put together, I badly wish I had just put together a decent but not exotic medium stroker BB (in the just under 600 CID range) for my temporary mill and got much more than I hoped for less and none of the "professional" screw ups I got with this SB. (Nor would I have waited almost five MONTHS for this "professional effort" to finally be delivered....) I hope I never again will doubt my own efforts versus those of a "pro."

Aflac

I have been looking at the motown blocka and trying to figure out what borexstroke they used to get to the magical #...

WayneLBurnham

says....

427.....4.0 stroke.....4.125" bore.....

(of course you have to guess the exact spot, but I was surprised how close that is - stnd. 400sbc bore IS 4.125"!)

My 413 (really a 412.7) is 4.185" with a 3.75" stnd. 400sbc stroke.

Aflac

thanks! I was looking at some dimensions and was wondering what the best way to get there was!

turtlevette

If it were that easy SB 427s wouldn't be 12 grand.

To get a 4" stroke you probably need a aftermarket block with raised cam and wider oil pan rails.

Schmucker

The cam isn't moved. 454 is the largest small block with stock valve location. The 472 or whatever that was built is a raised cam.

WayneLBurnham

No need to change to DRCE type oil rails or anything...

$12K is the kind of price my idiotic self would be required to pay too! You can get the whole balanced rotating assy for that for under $2500-3000 - all high end forged components, add another $400 for the block and $500-$750 for machining and such and the various gasketry and such and one of these could be in the "just assemble it yourself" condition for $5Kish, $7.5-8 assembled by a reasonable shop.

The cost for me to have had mine turned into one was exactly the same, but my idiot just didn't recommend them. (Since he "always likes to use bronze distributor gears on everything" anyhow, that's probably just as well - we shouldn't want to overtax the guy's abilities.)

I'm....not.......BITTER or anything... no, not. at. ALL!

vetteaddic

4.125x4.00 427 ,4.155x4.00 434 I just installed a mowtown 427 ,that I bought threw jegs it was a shortblock for $4500,then got me a roller cam (small base circle) for big lift,you might not need a stroker pan but I got one and then bought some dart pro 1 230 heads,total package cost me around 7500, I could have bought their complete engine for that same price bu I wanted a different cam and heads,Ijust got back from cruising the 73 and punched it for the first time I about lost control Im kinda shakey ,it left a satisfied smile on my face

427V8

I built a 434, 4" stroke, 4.155" bore back in '99, using a 76 montecarlo 2 bolt block, trick flow forged crank, Lunatti 5.875" Rods and custom pistons. AFR 210 heads Moroso 191 pan splayed caps, Blah blah blah for 0nly $8000. And that includes assembly Breakin and Dyno by the areas top builder.

I went with a small ~.500" lift cam and it only puts out 460hp at 5800 PRM and 503 ft/lbs. The cam was supposed to be swapped out for a larger one but I haven't quite got around to that yet. It runs very well and is a blast on the street and the track. I'm afraid that if I change the cam it won't be as fun...

The block needs to be clearanced, you need a small base circle cam and stroker rods.

CorvetteDave01

I am definitely going to build either a 427, 434 or likely a 454 with a world motown block. I currently have a 383 with a Edelbrock proflo injection system and sportsman II iron heads and at least want to use the injection system. I contacted someone at Edelbrock and they emailed me back that the only thing that I need to do on the injection system is put heavier injectors in it, the fuelpump will go 625 hp as is even.

Can anyone verify this?

Anyway, there is a good series that started in Superchevy magazine called major mouse that is showing 427 sbc combinations, April and now May 05 just started this. I plan to watch what they do for my motor build, hopefully next year (I am rebuilding the drivetrain atm, Offset T-arms, tremec trany etc. and I am out of money). Apparently the only thing you need to modify with the iron blocks for the 4" stroke is the connecting rods, 6" in this case, although I have seen a build up of, I think they were 5.85" rods (something like that). They even used Edelbrock Etec 170 cc, 1.94 I.V. heads on the first 427 build up and got 510 hp or so and over 500 lbs of torque from 2500-6000 rpm. Of course this was on pump gas too. Pretty incredible really.

gkull

Poster are you talking H roller? At a minimum I would use AFR 210 heads and the comp ported model. Your better off with heads in the 300 CFM intake. Which would be 227cc type. Keep the compression up. I'm using Flat milled AFR heas to get the compression to 10.7 with .021 copper head gaskets.

The Pro's are: When combined with a three inch exhaust it makes for a healthy sounding motor. I've also noticed that all the kids in the hot fart pipe motors always stay away, like whipped dogs with tail between their legs. Out on the highway - no down shift and it's just a few seconds from my 85-90 cruise speed to 140 mph to get away from trucks and morons trying to box me in.

The Con's: Your car is going to shake at the stop lights even with a 1000 rpm idle. The cost to build high HP motors is $10,000. Then driving them is a learning curve. Your not going to use WOT from a dead start or on Fast freeway on ramps. Just in my limited testing I have no problem hanging the rear out and that blue haze of tire smoke following you. I was looking at my 315 rear tires when I came home and they look like somebody ruffed them up with a grinder. Very easy like VetteAddict pointed out to smoke the tires.

45ACP - I didn't take off a day for a long trip. I did manage to get 200 miles on it on the drive to the local road racing track. In the morning before going I raised the front end 3/4 of an inch more to give the tires some more clearance to the wheel well. They had a corvette 3 day road racing school going so did not get any real track time. It's a good thing because I managed to shear off the end of my 1 1/8th sway bar grade 8 3/8th inch bolt and blow a front shock. They had 70 Vettes in the Racing School. Probably 1/2 Z-06's Lots of C-6's.

Any way at 200 miles on the fresh roller cammed 427 Motown I've felt a little more at ease about giving it some throttle on occasion. But just keeping the rev's under 4000 rpm.

Yesterday out at the road racing track

CorvetteDave01

What offset wheels are those gkull? I am wanting to get some 17" wheels on mine eventually.

CorvetteDave01

Do you have any pictures from the rear of your vette?

45ACP

HAHAHAHAHA!


How did you break that stuff? Did you run something over?


What are you going to use for a redline? 7000?

CorvetteDave01

I have seen lower block 427 motown assemblies (block, crank, rods, pistons etc) for $4,400 or so by they way. Can't remember where I saw this off hand, but if you already have some decent heads, intake and carb, you could, I would think, get one going for 5k-6k or so.

gkull

Dale - When removed the front springs to put a 3/8th in hard rubber spacer to lift the front end a little. I was using air tools. So I must have made the 6 inch long bolt with poly spacers to tight. I drove easy and got the tires up to heat. The first major high "G" turn that I stomped on the brakes to dive into I heard a major bang. As soon as the end of the sway bar came off, the shock bottomed out and blew it's seals and was leaking oil all over. No biggy. I just went and Bought a new grade 8 six inches long with grade 8 nylock nut and set it correctly. I just have to get a new front shock.

All dyno simulations were done with 7000 rpm red line. max power is over 6200 rpm. It's smooth motor and I'm not worried about it.

groovyjay

That's what I'm getting!