427 stroker build

[427supr]

Guys, I have decided to scrap the 408 build and go for the gusto and build a 427 stroker. I am going to go with a Dart Iron Eagle block, with a 4.125 bore and a 4.000 stroker crank, or a 4.000 bore and a 4.170 stroker crankshaft. Which is a better combination? I am also looking to purchase a 427 stroker kit rather than buying the short block components seperately. I am looking for any suggestions on this build form guys who went this route, and a good company to purchase a stroker kit. I will primarily using the cobra on the street. I am leaning towards Scat and Eagle components.

Thanks,

Gary

[Dwight]

I'm not an expert but I would go with the 4.125 x 4.00". Higher rpm motor. You may lose a little torque at low rpms but your pushing a lite car. Watch what trannie, tire size and rear end gears you pick. Picking the correct components and you will have a great street machine. Quick off the lights and great cruise speed (rpms).

I'm a small block guy but I have 8 or 9 FEs in the shop. One of these day I would like to build a GT 40 with an FE.

This is going to be a very informative thread


Dwight

[Dennis Kelley]

IF it was me I would do a 4 inch stroke and 4.125 bore.
later
dennis

[bobcowan]

I did the 4" stroke, and 4.125 bore. Less stroke means less side loading and higher rpm's. I had Mike Forte put mine together with an Eagle kit. It makes a really flat torque curve at about 450ft/lbs on the chassis dyno.

This is kinda odd, though. I replaced a stock block 427 with the Dart 427. That engine had a nice cam that made solid power to red line. I put that cam in the new engine, and it fell on it's face. Replaced the cam with something differant, it woke it up. Why did that happen? I have no idea.

The car runs great. Gobs of torque. Really fast out of the corners. On the rare occasion I take it to the drag strip, it doesn't do well. The best I could get is 12.04/112. Just can't get traction. But it's not really set up for the strip; it's set up for the road course.

[CHRIS DAMSCH]

Bob,

What is the rest of your combination(heads, cam specs, intake, comp. ratio)? Can you post your chassis dyno sheet? Or maybe some hp and tq #'s at different rpms.

Thanks,

[blykins]

Do you have to have 427 ci? If not, I'd go for some big cubes. The bigger displacement, the more streetable power you can make. Search for my 445ci thread.

[olddog]

Obviously either engine can be built and made to run. Usually each approach requires robbing Peater to pay Paul or visa versa. So it's a matter of choosing your poison. I suggest understanding the costs, and drawbacks with each.

For example, one point to consider. On the block you plan to use for a 4.125 bore, how thin will the cylinder walls be? Will there be adaquate room to bore further on the next rebuild? However this may not be important to you.

On the longer stroke option, what needs to be done to the block for clearances? How close are the wrist pins to the rings? Are you forced to thin rings and do they seal up well? What has to be done to get it ballanced up.

[brettco]

I say 4.125 x 4.170 .

[TXWOOD]

why not go with a Probe rotating assembly, then you have bragging rights to no chinese iron in your engine. Probe is USA made or Crower (high dollar) or HTC.

[427supr]

I am running Edelbrock Victor Jr. type heads with a 60cc. My engine builder has Reed Cams do custom grinds on whatever the customer is looking for. I would like to run a hyd. roller, and rockers. I am not sure yet on the lift and duration. A Edelbrock Super Victor or maybe a dual plane. Any suggestions on a good dual plane for this build? Holley 750 with mech. secondaries. Hoping to be around 550 HP. I will stick with my current tremec and 3.73 rearend. Mostly using cobra for the street.

Build so far:
Dart Iron Eagle block 4.125 bore
Scat forged 4340 crankshaft. 4.000 stroke
Summit forged 4340 H-beam connecting rods/6.200 inch
Victor Jr. type aluminum heads. 60cc

[Manowar]

You will not get to 550Hp with a dual plane and 750. (too little induction)
Nor with a Super Victor.(too much manifold). A Victor Jr. with 850 might if your cam is stout enough. Be careful of piston spec with 60cc chambers.

[MFE III]

My 427w (built by Smeding Performance) is 4.125 bore/ 4.0 stroke. I agree with the theory of going with the shorter stroke to minimize side wall pressure. Mine dynoed out to 550 hp/560 tq at the flywheel. Here's a link to the build specs:
http://http://www.smedingperformance...braspecial.htm
Matt

[blykins]

A hydraulic roller would work fine for this engine. With the right springs, you could make peak at around 6000-6200. I agree, a dual plane wouldn't give you what you want. I'd go with a Victor Jr.

BTW, I sell Probe rotating assemblies, pistons, cranks, rods, rings, etc. I also sell Jones custom cams. Shoot me an email if you'd like to talk about products. I can guide you in the right direction.

[jshel1]

I found this page extremely informative in helping my decision on Windsor SBF stroker; particularly the discussion on page 2.

Stroker Motors Explained - Stroker Engines | FordMuscle.com

[bobcowan]

Originally Posted by CHRIS DAMSCH

Bob,

What is the rest of your combination(heads, cam specs, intake, comp. ratio)? Can you post your chassis dyno sheet? Or maybe some hp and tq #'s at different rpms.

Thanks,

I thought about more stroke for this engine. 455 cubes is pretty easy. But I like to beat on it pretty hard on the road course. So the shorter stroke will last a little longer. It's a trade off. If I was building a strictly street engine or maybe an occasional drag motor, I'd probably go for the longer stroke. Too much is just about right.

I'm using Dart Pro-1 heads. The runners are smaller than most aftermarket heads. But - in theory - they flow well enough as is. And they're cheaper. I port matched them to my intake. Otherwise I left the ports and chambers alone. I did use Comp Cams beehive springs.

The cam is a Hydraulic retrofit roller from Coast High. Basicly, the biggest one the sell. .595/.605, 294.298. It starts to break up at about 6,300 rpm's. Valve float I suspect. I think next year I might go with a solid roller cam for more rpm's.

I have 10.8 static compression. But I live at 6,400' ASL, so cylinder pressures are pretty managable; especially with such a big cam. On the street I run mid grade fuel without any problems.

The intake is a Momar EFI 8 stack system. By looking at the dyno chart, there dosn't seem to be any problems with air or fuel delivery. If I can get more rpm's in there, I think it will run just fine. I don't think the intake or heads will be restrictive. We'll see.

[427supr]

The Victor Jr. is fine. I thought the dual plane gave you better low end torque at lower rpm's and the single plain gave you more HP on the higher rpm's. My engine builder believes that a smaller carb (750) runs better on the street than a bigger (850). Bigger is not always better. Some guys over carb, but I will talk to him about it. I personaly would rather run a (850). My engine builder is hard to argue with because he works for a well known engine builder that builds nascar engines for winning teams.

[Manowar]

Get opinions from other engine builders.
Here's one formula we build for 500+HP for pump-gas street usage. These regularly make 535-540 on their 525 rating. The next milder "World Class" build uses an 870 and is rated 495. These are street/dual purpose engines. We have many Cobras running with them.
427 Man O'War Hardcore High Performance Street Small Block Ford Crate Engine