I was afflicted with the convertible bug FOUR decades ago with the purchase of the '68 GTS. Still have it along with the '67 Barracuda. One of these days both cars will be finished again. Side by side a few years ago.
I really doubt that a .3 drop in compression would account for that much power loss. I do suspect that the addition of the catalytic convertor, which in those days was very restrictive, single exhaust, carb and distributor changes for smog, lean burn, and other things like less cam caused the...
I don't have concrete evidence, but to my knowledge both '78 and '79 LRE's were available in California. As for how a smog pump works, I have a theory. They claim it allows for unburned gasoline in the exhaust to burn due to the introduction of more oxygen. My theory is that all it does is...
If you're on Facebook, look up Sam Bledsoe. He's in central California and has a very unmolested LRE, which I seem to recall being a '79. He's been around these '72-80 truck for a long time and has parted out many.
I bought some low profile LCA bumpers from Summit. They're more like buttons. We have also cut some factory ones down. I like to have about an inch between the bumper and frame.
Energy Suspension 9.9102G Energy Suspension Bump Stops | Summit Racing
The VIN on the engine in on the pan rail, not the front of the block. The front of the block has the build information for the engine only. ALL 1971 340s had Thermoquads.
In the real world with similar builds the performance will probably be similar. There's no real 383 vs. 360 performance tests from the 1960s, but there is 340 vs. 383 and they ran similar numbers with the 340 maybe being a little quicker.