Good day everyone. Some might recall my experience with the original engine in my 67 GS400 where the piston cracked to pieces. Being that the block was already 60 over, many recommended to get a replaceable engine and start from scratch. Well I did just that. I found a 73 455 engine, unmolested with low miles. Currently 455 and parts of my 400 are sitting at Scotty's racing engines for him to build. With this said, I am no expert in such engines and not familiar what route to go when building the 455. I can say the following of parts in my 400 that I plan to reuse: 1. It has a comp cams muth thumpr 2. TA roller rockers 3. Poston oil pan 4. Possible the 430 heads 5. Piston rods 6. Rebuild the quadrajet carb I do not do any racing, just cruising, but obviously want the best possible build within my budget. In speaking with Scott, he said he wants to see the 430 heads to see which are in better shape vs the ones on the 455. He also said we can take the engine over to stage 1. In my readings I see mentions of bearing clearances, deck cuts, etc... and honestly I have no idea what they are referring to. With all this said, if you can provide some guidance on what I should be looking into when building this 455, I would greatly appreciate it. Thank you
I would let Scotty select the cam. Be sure to select one that allows the engine to make enough vacuum to operate power brakes. Too much cam in a given street engine can actually slow the car down.
In my opinion, Mutha Thumpers are for impressing people in parking lots & cruise-ins. Take Jim's advice and let Scotty pick a cam for your combo.
Supposedly the BBB 400 blocks are thick enough to bore to the 430 bore size(.147" over the 400 bore size of 4.040") so don't scrap your original block because it is only .060" over!
Just tell Scotty what you want to do with it, sit back and let him do the parts selection, he knows what's up
Thanks for all input. As for the cam, he asked me if I liked it and if there were no issues with it, it can be reused. I will pick his brains again on cam selection, but out of curiosity, what is normally used/recommended for such engines?
Scotty will probably recommend a cam in the 230-240 @ .050 range with at least .500 lift and possibly a 110 LSA. Should sound quite healthy and push out near 500 ft/lbs and 450 hp if the short block is zero decked. If its a stock short block you should focus your budget there instead.
That is good, but what do you plan for the shortblock? I think you may need to sit down with Scotty and talk about it. We are having trouble because its hard to define performance without a given set of information, besides a single cam grind.
As for the block, pending for him to take apart the engine he has on hand and come up with a plan. I was able to provide him with a long block to rebuild.
The piston probably cracked because of the cam. The relatively short intake seat timing coupled with the 102 deg Intake center line results in an early intake valve closng event. That drives cylinder pressure way up and can cause detonation. I am very curious about the condition of the rod bearings, they may show signs of stress (like metal pounded out) due to detonation. Let an expert guide you
Actually it was determined to be a very poor engine rebuild. The heads had mismatched valves. The valves where never seated correctly as you can on the pistons the new groves it has created. Engine probably had 2-3k miles after rebuild and there was no abuse on it. Basic cruising driving. As for the rebuild it was done before my time so I had no saying in it. This is why I’m looking for feedback for this rebuild along with Scotty’s. Reason why I took it to him as he is fairly near and reputable Buick engine rebuilder. Thanks
