I am thinking about building my 72 400 sbc engine. It runs great right now but it was rebuilt about 20 years ago, when my uncle owned it. I want to amp it up just a little. I need you guys opinion on what things to do to it. Let me know what else you guys think I should use. I am not wanting a race engine. I just want something nice and powerful with a hard thump. I am using the following parts:
Looks like you on the right path for a good build only thing i would do different is go with a extreme energy 268 or 274 cams only because ive hearde to many conficting stories about those thumper cams there made to give you sound doesnt make sense to me.
What cylinder heads are you going to run on this engine? If you are going to be running some with a 76cc chamber you may want to look into using a flattop piston with a cam that has that much overlap. 76cc with a flattop will get you to around 10:1, dished pistons will be around 9:1. 64cc and a dish will be around 10:1 and 64cc with a flattop will be a way too high 11.5:1 or so. I agree with ElCaminoGRAN/SPORT from my experience the Thumper cams make more "sound" than power. The engine I just built for my 1989 K1500 is almost a little too much, but I had all the parts sitting on the shelf just beggin' to be used. I used a 0.040 over 400, stock crank, stock polished beam rods with ARP bolts, dished KB Silvolites, RPM Air Gap intake, a set of the old TrickFlow G2 Twisted wedge heads, 1.6 full roller rockers, a XE274 Comp cam, and a 750 carb, with Hedman long tubes. It dynoed 494 hp @ 5700 and 521 lbft @ 4100 it was an inexpensive build of just left over parts that runs badass and has been knockin' down 16 mpg as long as you stay out of the secondaries. So I would say go with the XE274 and a set of Vortecs (or similar flow), Airgap, and good carb and exhaust and you could make good power for cheap
So what cylinder heads you planning to run? And are you gonna run headers? Also what gears and converter you planning to use? This will have to work hand in hand with the cam and other parts.
Im going to use the stock heads but get them redone. Im using a 2500 stall and Im not sure if I need to buy rocker arms and push rods also, this is my first build. I am going to get some headers too. Im using the comp cam 2100 gear set
Check prices before you have them "redone." Depending on what they need you may be able to buy aftermarket heads, like vortecs for the price of having a set of heads completely rebuilt. Vortecs are just an example, not sure what pistons you have in there or cam you plan on buying.
I'm with crotchss on several points. I am a huge fan of the Extreme Energy cam line. Don't get too greedy with your selection. The important thing to keep in mind with a 400 is that it makes great torque. Try to capitalize on that. There is usually no need for a "big" cam when you are focusing on torque rather than peak HP. I also agree that money spent for a set of better heads is wise. Don't forget to drill the steam holes. You may not need to completely rebuild your bottom end anyway. If it's already been rebuilt there may not be another overbore left on the block. Many will say .040" is max. I have one that is at .060" but it has a tendency to run warm when I pull a long hill.
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