408 vs. 418

LMH · #1 (**permalink**) 01-14-2009, 07:21 AM

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

Ron61 · #2 (**permalink**) 01-14-2009, 09:00 AM

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 · #3 (**permalink**) 01-14-2009, 10:08 AM

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.

Fordzilla · #4 (**permalink**) 01-15-2009, 05:06 AM

Quote:

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 · #5 (**permalink**) 01-15-2009, 05:09 AM

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.

olddog · #6 (**permalink**) 01-15-2009, 01:06 PM

Quote:

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 · #7 (**permalink**) 01-15-2009, 01:12 PM

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.

olddog · #8 (**permalink**) 01-15-2009, 01:27 PM

Sorry. I somehow double posted editing out a typo.

olddog · #9 (**permalink**) 01-14-2009, 08:27 PM

Quote:

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 · #10 (**permalink**) 01-14-2009, 09:24 PM

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 · #11 (**permalink**) 01-15-2009, 02:59 AM

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 · #12 (**permalink**) 01-15-2009, 05:04 AM

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.