Now back to assembly. We went with a lightweight Probe SFI race damper-an elastomer unit w
As we completed our story last month, our prepped 360 bottom-end was stuffed with a Mopar Performance stroker crank and built up into a stout little short-block. The MP crank stretched the cubes to 408, while Milodon four-bolt main caps, Eagle H-beam rods, and a set of Diamond forged stroker flat tops provided the beef.
To show we were serious, we were also packing a serious but sane Crane roller cam, spun by Milodon's excellent gear drive. We had horsepower in mind for this combo, and the top end wasn't going to hold us back. We ground ourselves silly getting huge flow from a set of W-2s (Nov. 2001 p.54), and the ante just kept getting stepped up. Getting ready for this month's installment, we found that Mopar was dealing on tunnel-rams, so we added one to the program-though a more conservative (by comparison) single-plane is also part of the mix for the dyno test to come.
We found that with the pan on, the edges of the tray were pushed in slightly, enough to ca
Building a hot engine combo gets tougher the more radical you go, and though this isn't an all-out race engine, our 408 is much more involved than screwing together a basic stock-style 360. Therefore, it's up to the engine builder to make sure everything is right, from ordering parts that will complement each other, to making them fit together like they should. We can't wait to hear this one singing on the dyno, but before that happens, it's all wrenching, grinding, measuring, and checking. When all's said and done, and we've buttoned on the last piece, hearing the sweet sound of our "mini-mountain" small-block pull will make it all worthwhile.
Double-Checking Pays Off
We thought the bottom end of our big-inch small-block was sewn up for good last month, but a lucky catch saved us from potential problems inside. We carefully checked and set the clearance between the Milodon windage tray and the moving hardware swinging above, dropped the pan in place, and buttoned it up.
The tray was bolted back in and the position of the dimples verified in line with the rods
Here's the deal. The sides of the pan press against the sides of the tray when it's bolted up, squeezing the ends of the tray in toward the crank. This is not a problem with a stock stroke, but with the 4-inch arm, it pushes in the louvers of the tray towards the rods. It may not hit, but it may be too close for comfort. Luckily, we heard a slight interference inside and opened it up to investigate. Pan-off, plenty of clearance; pan on, contact. The fix was simple-we just marked the lower louvers in line with the rods and dimpled for a margin of safety.
The Ups And Downs of Cam Peripherals
We had milled, long-stem-type Econo W-2 heads, plus solid roller lifters and aluminum rockers. No, there won't be a cataloged pushrod for this combination. The truth is, any time the valvetrain or related components are changed, things have to be measured. For us, a set of custom pushrods were a given, so we tackled the challenge of figuring out what we'd need and then ordered them from Crane.
The piston's deck height is measured with the engine assembled or mocked-up. We dialed in
The pushrod length is measured by mocking up the heads with the cam and a pair of rockers
The chamber volume is measured by "cc'ing" the heads. Our W-2's were machined to give 66 c
With the valvetrain functioning, the valve-to-piston clearance is checked. This really sho
Though the above check will give the clearance, it won't sound an alarm if the valve's rad
With the clay in place, bolt the head back on, set up the valvetrain, and rotate the engin