408 vs. 418

[427supr]

I've been pricing Eagle kits for a 408 and a 418 from Summit. The less expensive 408 with a cast steel crank is about 1/2 price of the forged crank 418 kit. I am aware the forged is a better option, but for street use the cast steel is fine. Other than the stroke of 4.00 of the 408 and 4.10 of the 418, using the same engine components, would there be a big difference in HP & torque between the 408 & the 418 engines? I was told using a stock block, not to go over the 4.00 stroke, but some builders I've talked to advised the 4.10 stroke is fine with the stock block, but is pushing it with a 4.170 stroke.

[vector1]

i'd do the 4". seems the larger stroke never ends up doing what people think, as in hp & tq. also, you see a ****load of 4" stroke stuff, very few 4.1, prob a reason.

[coosawjack]

I built a 408 primarily because the larger displacement kits put the wrist pins in the oil ring lands and I was concerned about oil consumption.....the Eagle 408 kit uses inserts to control oil!!

The other thing we found is notching cylinder skirts on stock blocks to clear the crank weights and rods becomes more pronounced with higher displacement kits??

I have heard that the 393 kits are much simpler and make almost as much power as the 400+ kits!!

My $.02 FWIW!!

Coosawjack

[LMH]

I like the 393 kit better for a production block. Less piston speed and better rod angle = better RPM potential.
Larry

[Ron61]

I had a 418 in my Cobra and a 408 in the Coupe and I really couldn't tell much difference as I drove them both hard and never had a problem with either. The 418 put out more power but that was by design as the 408 would put out as much, I just felt that I don't need as much power as the 418 produced. When built right, I think both are great engines.

Ron

[blykins]

I have built two Windsors with 4.100" stroke crankshafts. The ring pack is not in the wrist pin.

The 418 will make more torque than the 408. The extra .100" stroke will make a difference....just a guess, but probably 20-30lb-ft more at peak and a little more average power/torque across the whole range.

I always like the longer stroke engines and with the 9.500" deck height of the Windsor, to me it's a no brainer.

The only difference is that you will probably have to do a tad bit of grinding with the 4.100" stroke.

I'd aim for the Eagle forged 4.100" stroke crank, and a set of Scat forged I-beam rods. That will help offset the cost of the expensive H-beams, and they will hold every bit of the power that you'll make with a wild street engine. You can find the SBC 6.200" forged I-beams with capscrews for about $220-230.

Keith Black makes a great set of forged pistons that will work good with the 4.100" stroke. You can get them for about $350-375.

Go for the cubes.....if you're not turning 7000 rpm, you don't need a shorter stroke. The 4.100" stroke will turn some revs with a good solid roller camshaft.

Aim for the setup that does the most in your desired power range. A short stroke engine that makes good power at peak, but not a lot of torque down low doesn't really accomplish much when you're tooling around in 5th gear. With the 418, you can make as much power (if not more) as the 393/408, but have the bottom end to make it fun too.

[olddog]

Originally Posted by LMH

I like the 393 kit better for a production block. Less piston speed and better rod angle = better RPM potential.
Larry

Since the 393 uses a windor rod of just under 6" and the 408 uses the 360 Dodge rod that is 6.2" the rod ratio of these two are almost identical at about 1.55.

The 4.10 stroke with a 6.2" rod drops the rod ratio to 1.51.

With the windsors 3" mains, some claim it should be limited to 6500 rpm anyway due to the oiling issue. Others claim it can still turn 8000 rpm if the oil pressue stays above 60 psi. If only I new the trueth!

[jshel1]

I decided on the 408 based upon the following:

http://www.fordmuscle.com/archives/2003/09/stroker/
http://www.fordracingparts.com/crate...eightliter.asp

Ford does not offer a larger factory crate than the 392 for the reasons bandied about by some posting here, and from what I have heard, concern about warranty issues.

[blykins]

Yeah, but they don't offer a 482ci or 505ci FE either....or a 557ci BBF for that matter. (Plus they offer a 427ci SBF now....check the 2009 catalog.)

[jshel1]

Haven't seen the 2009 catalog yet, thanks. I did double check the pages I had book marked during my engine selection phase. Ford must be watching the speedshops making the money on 408, 418, and 427's and want their piece of the action.

My rev limiter is set for 6000 because of the possible oiling restriction.

[Fordzilla]

Originally Posted by blykins

Go for the cubes.....if you're not turning 7000 rpm, you don't need a shorter stroke.

This is my general rule of thumb, go for cubes, You just can't beat cubes!

[blykins]

I'd like to see where you got your info on the Windsor oiling restrictions. I always knew that there was a possible issue with Cleveland blocks, thus the need to bush the lifter bores, run external oil lines, etc. But as far as Windsors are concerned, 302s/331s/347s are dialed up pretty high without problem, as well as some 357s/393s/408s that I've seen. 6000 rpm seems *extremely* conservative as I've spun them a lot higher than that.

[blykins]

BTW, 427supr, if you want some more experience on the 4.100" stroke Windsors, Terry Stapley (a CC member) is also running a 418W and has been for years.

[427supr]

I've been thinking about stroking my 351 for a while now. It's a hard decision, the car is running very good. Never had problems with it. You know the old saying, "if it ain't broke, don't fix it." But the testosterone always wants more power, that I will rarely use on the street. I even thought of pulling the motor and selling it. Buy a Dart block with the big bore 4.125 with a 4.000 inch stroke and build that magical 427 windsor.

[blykins]

It would be a kick in the pants, that's for sure. Power levels from a stroked Windsor are nothing short of awesome.

If I were going to sell out and start new with a Dart block, I wouldn't stop at 427ci. I'd use the big bore, and as long of a stroke as I could stuff in there. A 4.125" bore with a 4.25" stroke would be 454-460ci and would have as much power and torque as you could shake a stick at. A 427W isn't nothing special to me for a Cobra, just because it's not anything near an FE. From my experiences, you tell them it's a 427, then they look for themselves, and then ask why you didn't go with an FE.

[TerrysSPF]

The Dart block is the way to go for sure - especially if you want to go past 418 cubes (IMHO). But I guess it depends on how much power you're looking for.
It isn't that hard to get into the 500+HP range out of a 418, 408, or even a 393 with todays parts / technology.

Are you familiar with DSS? These guys are near me and i've always like them. They offer some great stroker kits: www.dssracing.com

[jdean]

Has anyone noticed that the Chevy 408 is the newer better 383? So us Ford folks need to do them one better with the 418. They seem to be gaining a lot of popularity.....more and more showing up at the dragstrip.

I went with the 418 with the forged Eagle 4.1 crank...cost the same as the 408, but seemed like a good compromise between the 408 and 427 for a stock 351 block. I have had both a stroked 460 (521) and a 427 FE so I appreciate the larger cubes and the low end torque that comes with it.

[blykins]

Atta boy John....

The 406/408SBC's are based on a 400SBC block. It's easy to get to 406, it's just a .030" overbore. To do that with a 350 block, you really have to do some stroking and grinding.

[olddog]

Originally Posted by blykins

I'd like to see where you got your info on the Windsor oiling restrictions. I always knew that there was a possible issue with Cleveland blocks, thus the need to bush the lifter bores, run external oil lines, etc. But as far as Windsors are concerned, 302s/331s/347s are dialed up pretty high without problem, as well as some 357s/393s/408s that I've seen. 6000 rpm seems *extremely* conservative as I've spun them a lot higher than that.

I have read lots of comments in books, magazines, and on the net where people claim the 3" main journals are too large to handle high rpms. They say it about the 385 series as well as the Windsor. The block's oils system is not the problem.

If you compare a SB main journal of 2-1/4" vs the 351W at 3", A SB turning 10,000 rpm would have the same journal suface speed as a 351W turning 7,500 rpm.

The surface speed shear thins the oil. The viscousity goes down with the shear rate in the bearing. Anyway this is what I had assumed was the issue with the comments that the 3" journal limits the rpm. The other day I read an artical describing the problem as one of centrifugal forces. They explained that the oil spinning in the bearing generates a centrifugal force that is trying to push the oil back into the block against the oil pump that trying to feed the bearing. They recomended keeping oil pressures high for high rpm applications, with 60 psi as the minimum. The FE with its 2-3/4" main has always ran very high oil pressures to survive high rpm use.

I know the shear thinning is real, and the centrifugal theory makes sense, as well. If the centrifugal force reduces the rate that the oil is flowing into the bearing, then the oil in the bearing will be subjected to the shearing longer and that increases temp and reduces viscosity. Certainly these two things would have a sinergistic affect taking you towards the fairlure point.

What I don't know, is exactly where the real world limits are. I know people who are spinning 408W to 7500 rpm drag racing. That same engine may not take that same rpm on a circle track, where it would stay at those rpms much longer. Perhaps they can turn even more, this is what I have been trying to sort out. I see comments saying they can turn 8000 rpm all day others saying do not go over 6000. I don't know what the limits actually are. I never built one, never owned one, never saw one fail. It is all research at this point, for me.

I did see one stroker kit that had 2-3/4" main journals with extra thick bearing shells. I have seen this with the SB 400 Chevy for years. I know some circle track guys who run the smaller 350 main journal by turning down the 400 crank. They also claim this allows higher rpms.

[blykins]

Most of the aftermarket blocks use the Cleveland (2.75) mains as well. My 445ci Windsor with the Dart block used a 4.100" Cleveland style crankshaft.

That engine was a hodge-podge....Windsor block, Cleveland mains, SBC rods....

However, I can pretty much guarantee that the ones that are saying that the regular Windsors can't go over 6000 rpm are pretty much in error.