[MrArt2u]

I’m sad to report that the Flat Tappet Hydraulic Lifter Catastrophic Failure Club has a new member. The 400 in my ’64 Bonneville convertible chewed up the number 7 exhaust lifter pretty good. The motor was built just about 20 years ago but only has about 4,000 miles on the clock. I got tons of advice back then from this very forum. Old Man Taylor, TATodd, Tom S. And so many more, all answered tons of questions. So I’m back for fresh advice. Reading through the forum, it looks like a lot has changed in the high performance Pontiac world over the last 20 years.

I’ll need some advice on what may have caused this and what to do next. So far, I’ve only gone so far as pulling the intake and valley cover and pulling the bad #7 exhaust lifter. There was close to a quarter of an inch ground off that lifter so I know the motor has to come out for proper cleaning, how far do you guys go? Complete strip down? Do you typically replace all the bearings? Rings?

Does the fact that it was the last camshaft lobe mean anything?

Part two: Need new cam advice.

I’m also looking for new cam selection advice. I was considering a roller cam but, wow, what a price difference. Is it worth it? Stick with Flat Tappet? I’m strictly a street, no strip driver and getting older so much more of a cruiser these days. I’m looking for a reliable motor that pays respect to the legendary Pontiac power.

Here are my current specs:

1964 Bonneville convertible (3,985 lbs.) 400 engine block. 62 heads with some port work. This motor belonged to an old friend that passed away almost 30 years ago. He used to street race it in his 64 GP with nitrous so it absolutely needed a rebuild by the time it got to me. He did the cylinder head port work himself.

According to the receipts from my rebuild, the engine has L2262 .030 pistons and a Comp Cams 275 DEH Dual Energy HFT cam with Comp Cams High Energy 852-16 lifters. Do these pistons give me too high compression for street?

The 62 heads have ARP rocker studs, guide plates, 1.52 Comp Cams roller tip rockers and have had port work. Springs have 120 lbs seat pressure.

1966 Tripower, spec’d by Old Man Taylor. Mallory distributor, MSD box.
Exhaust is factory cast iron long branch headers and a pair of nice mufflers.

The transmission is a 700r4 rebuilt with B&M components and a B&M Holeshot 1900-2100 stall locking torque converter. 4.10 posi rear end. With about a 29” tall rear tire (255/70-15)

The car had tons of power early on, almost too much for my driving style, but, man, was that idle a sexy rumble. Recently it felt like it was gradually dropping in power and had trouble with detonation. (failing lifter cause the detonation? Or is it due to that high compression ratio and today’s gas?)

Thanks!