Quote:
Originally Posted by SS427
The engine was rebuilt by our own Eric Jackson (Vintage Muscle Car Parts) who did a great job pulling 478 hp at 5500 rpm and 472 ft pounds of torque at, get this, 3500 rpm. This thing will have some power though I am told by a certain young lady that I will never find out just how much. We made absolutely no power adders on this engine and it was rebuilt stock. Stock bore, crank, rods, pistons, a nostalgic cam with factory specs, stock heads and intake. Only the carb and distributor was blueprinted. After completion Eric worked with "Ohio George" Montgomery and dynoed the engine. Kudos to Eric for getting this thing done and with that much power. In comparison, our LS6 454 engines (that I have rebuilt locally) are generally .040-.060 over bore and otherwise stock and pull 475-498 horse so I am very pleased with the results. Correct me on any of this information Eric if I am listing it incorrectly.
|
Rick;
Sorry for the delayed response.
The engine is .030" over--strangely enough, when we checked the bores on initial examination, they were actually pretty straight--but they were just over .002" oversize, which would've left .0075"+ piston to wall clearance with the original pistons. That would've rattled like hell when it was cold which obviously wouldn't do, so we had to go .030" with new pistons to get the wall clearance where we wanted it.
The heads are bone stock with 2.19/1.72 valves and a 3 angle valve job, that's it.
The cam is pretty close to the factory 143, but with a little less duration and a touch more lift (I never divulge exact cam specs, that's up to Rick if he wants to reveal them). The LSA is fairly close to stock, and it idles much as the 143 cam would.
Since this is a 4 speed car with a 4.10 gear, Rick & I initially discussed spicing things up just a little, but since this car will never be pounded on and hero dyno #'s weren't part of the plan, I decided to try to pick up as much low end and mid-range torque as I could w/o sacrificing anything up top. I'm pretty happy with the results, esp. considering it surpassed my goals (460 lb.ft, 475 HP) on the very first pull. FWIW, coolant temp was 180° and total timing was 36°.
I wasn't able to test with the headers I wanted to use which I know for 100% fact cost at least 20+ lb.ft <4000 rpm. The plenum divider was left intact as well, which left another ~20 HP upstairs on the table, but I didn't want to sacrifice the low end torque to get it. We also could've cooled the engine down to ~130° and found another ~15 HP, but again, hero #'s weren't the objective and I wasn't going to go pounding on the #'s matching engine to a $200K+ car just for bragging rights.
I want to thank Rick again for the opportunity to play such a large part in this build. I'm honored, and I'm grateful.