Help: Builing a Street 408

J Persons · #1 (**permalink**) 12-12-2008, 10:40 AM

If you have an extra hydraulic lifter, disassemble it, clean it in carb cleaner and fill it with epoxy, then re assemble. It will act as a solid lifter for checking purposes. No worries about the lifter collapsing under spring pressure or anything. Just be sure and don't install it in the engine during final assembly.

If you have stud mounted rockers and hydraulic lifters, you can gain 200 to 300 more RPM if you adjust the lash so that it's at 0, then lock it down. This will put the lifter plunger at the top of its travel, and will prevent lifter pump up at high RPM. Adjust the valves at operating temp. Trade off is they can sometimes be noisy.

donraye · #2 (**permalink**) 12-25-2008, 03:36 AM

Hi all, I have just about every big and little thing for the 408 build now and have just pulled the 351 out of the car, so I will be starting the buld soon.
I will be robbing a lot of periferals from the 351 but some things will not transfer like the flywheel and the balancer which are both 28.8 oz. external balance and I will need neutral balance since the 408 is internally balanced.
But the question I now have for anyone is:
I have a perfectly functioning 10.4" OEM type clutch and pressure plate set-up with only 1,700 miles on it. I need to know if it will stand up to the 500+ crank HP of the 408 or not.
It will not be raced but of course there will be the glorious at least occasional "lead foot" (as one reason I have a Cobra to begin with!).
Will I need to just forget about the OEM clutch and get a Centerforce (or some other) that has about 90% more holding force than the stock unit? Or can I get by reasonably well with stock?
I hate to spend the extra dough at this point but would would hate to be replacing the clutch soon to put one in then even more!
One reason i hate to go to a new clutch pressure plate, etc. is that I think it will make the intall harder since the bellhousing/tranny are still in the car and the onld broken in clutch would mate up a lot easier than a new one when I put the new engine back in. I would that make that much difference? Was hoping to not have to disturb the stuff still in the frame/car.
Don

bermblaster41 · #3 (**permalink**) 12-25-2008, 05:33 AM

I have a 408 in my cobra. Building a fair amount of power. I had the same decision as you to use a known good used clutch. The last thing you want to do is pull the trans because your clutch won't hold. I went with a new clutch from ram. Not sure if I would go with their product again. Requires a great deal of leg strength to push it in. {I have a hydraulic clutch} I am sure others will chime in on their choice and which one has an easier pressure but still holds. Far as unbolting your clutch you will have to due to the pressure plate is bolted to your flywheel. A clutch alignment tool can be purchaced at any auto parts store. Hope this helps. Berm!

carmine · #4 (**permalink**) 12-25-2008, 08:41 AM

On a cobra being so light you really dont need anything bigger than 10.5 dia for clutch. Also makes it That much easyer to push the clutch peddle.

donraye · #5 (**permalink**) 12-25-2008, 02:29 PM

Quote:

Originally Posted by carmine

On a cobra being so light you really dont need anything bigger than 10.5 dia for clutch. Also makes it That much easyer to push the clutch peddle.

Carmine, Are you saying that you are using an OEM clutch or an aftermarket type in your Cobra. If you have an OEM, how many miles on it and is it holding up well so far?
D.