[bigbird90650]

Hi all. I'm a newbie here and I need some help. I have built a few small blocks before but never done a Big Block. Please help me. I just bought a 454 engine in pieces. It is mostly new but has been sitting in garage for a year. It is a 2 bolt freshly bored .030 over. It has a brand new forged steel crank, new forged rods, new forged Speed Pro dome pistons (Dome Height 0.221 in.), new sealed power moly rings, new clevite main and rod bearings P series, February 14th 1975 GM 336781 stock heads (are these heads any good?), and edelbrock 2.0 intake and 750 Holley double pumper. I need to choose a cam for it. I like comp's XE 284. It is going into a 1984 Chevy Silverado "Diesel" (not for long) truck. Truck weighs 4300 lbs. I am running a 400 trans and stall to be determined later. I don't know the rear end gear ratio yet. I want a pretty lopy idle and a stong mid range. I'm looking to get around 450 HP. Am I far off? Please give me some tips in building this motor. The crank, rods, cylinders main caps have some surface rust on them. What do I use to clean off the rust? I tried WD40 and it took some off. There is still some rust on the parts. Are they ruined or can I clean them up and be ok? How critical is this? Thanks

 

[furball8994]

First off, the heads are fare. 2.06 in/1.77 ex 113 (closed chamber) oval port. Second, take the block, crank and caps to a shop. It will need to be honed and the mains line honed to remove the rust. As for the cam, Go to comp cams site. they have a tek page. tell them what you have and what you want and they'll tell you the cam to use http://www.compcams.com/ bottom right corner

 

[Bob West]

781's are open chamber oval ports 118-119cc in stock form. The heads are great for your build and most any street/strip build, just add 2.19/1.88 valves and they're tough to beat. At 10-1, and a good cam,intake,carb and headers you'll make 500hp easy.

 

[furball8994]

Acording to my list http://www.chevymania.com/ they are 113 cc closed

 

[Bob West]

Your site is wrong, it even lists 049's as closed chambers, they are also open chamber oval ports.

http://www.mortec.com/bbc.htm

 

[theclencher]

I wouldn't throw money at machine work if it isn't needed. I've used muriatic acid to take rust off cylinders before and it works great.

 

[bigbird90650]

I only have 91 octane out here in CA. What would the highest CR I could get away with running this 91 crap? I guess I could add some octane booster to my gas if needed too. Is the edelbrock 2.0 a good intake? That is what I have now but was thinking of upgrading to the Performer RPM Air Gap. Will I see a big difference? Thanks.

 

[Jeff Wiebe]

First send everything to the machine shop and have it cleaned and checked. The 781 heads are 119cc open chamber, If you have 219 and 188 valves they will work great with a 10.5 piston on 91 octane gas. The 284h is a good street cam with a lumpy idle. You will need a 2800 stahl converter to run that cam efectively. A 780-850cfm carb will work best if the heads are ported with an air gap or single plane intake. You can use a 750cfm if there is no port work on the heads. I ran the same combination in my 4000 pound 71 Chevelle, with some port work, strip dominator intake, 850cfm carb and 4.10 gears with a turbo 400, the car was very streetable and ran 11.70 @ 115MPH. Est probably 500-525hp. at 6000rpm.