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BBC for first build?

23K views 199 replies 18 participants last post by  pohnjarker 
#1 ·
I'm still debating if i want to do a 383 stroker or a 454 build to put in my truck, 1971 C10.

the truck has a 350 in it so i was going to pull it and rebuild it into a 383 stroker. then i was told that the motor is too old to do that with and that i just need to get a new engine and rebuild that.

ok, no problem.

i start looking around and it seems like i can get a BBC/tranny for a few dollars more than i can get a SBC/tranny.

if im going to get something, tear it down and start a build, wouldnt it be a good idea to start with something a little "bigger" and go from there?

what do you think?
 
#132 ·
pohnjarker, When trying to figure your compression ratio you cannot guess at anything. If the block has not been milled then the deck is usually .025. Unless you special order the head gaskets they are usually .039 or .041. The kits offered by Scat either use -3 flat top pistons for a c.r. of 8.6. The other kit offered has +23 domed pistons for a c.r. of 10.5. Unless the heads have been milled 781's have 118cc-122cc chambers. They have to be measured. I would not use the kit with 10.5 c.r. unless I had aluminum heads. For the flat top pistons you really need a pair of heads with 108cc chambers, .010 deck clearance, and .030 head gasket thickness for 9.4 c.r. I would be afraid of detonation for anything above 9.6 with iron heads unless you want to spend the money on race gas.
 
#133 · (Edited)
yea...im watching tons of youtube videos on compression ratio and engine builds and they keep stressing to measure over and over. for something that goes down to .0000 should be spot on to work.

eta: the guy im getting the heads from said that the chambers are usually between 113cc and 118cc so to use 115cc as an estimate. he told me to wait until i need the heads to pick them up from him but since i know im going with the 781s, it would be better to get them now so i can cc them and find out exactly what it is so i can be exact in my calculations.
i have race gas available so i can always run that but you're right, id rather run 93 and be done with it. i ran some numbers and if i have a 12cc dome, it should be good at 9.5 so im trying to look for those but havent found any yet.
 
#136 ·
#144 ·
went and picked up the block today and dropped it off at the machinist to clean, magnaflux it, and see if it will bore out to .060. its sitting at .030 now. the guy i bought it from guaranteed it will bore out to .060 and if not, he will give me my money back and try to find me a block that will.

i also picked up the built 781s. they have howard springs good up to 600 lift, rotation eliminators, some little blue caps that go inside the springs(forget what they are called), thicker retainers, stud bolts, and larger valves...2.02/1.88 IIRC.

he also said that if i get a cam kit with different springs, to bring it back to him with the springs and he will swap them out for me free of charge and give me 100 bucks back for the springs. i think i got it all....

when i get the intake, he said bring him the heads, intake, and gasket and he will gasket port match the heads and intake for like 50 bucks.

here are a few pictures of the heads.





 
#149 ·
Summit Racing Part Number: CCA-K11-433-8

Cam Style: Hydraulic roller tappet
Basic Operating RPM Range: 2,500-6,000
Intake Duration at 050 inch Lift: 236
Exhaust Duration at 050 inch Lift: 242
Duration at 050 inch Lift: 236 int./242 exh.
Advertised Intake Duration: 288
Advertised Exhaust Duration: 294
Advertised Duration: 288 int./294 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.521 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.540 in.
Valve Lift with Factory Rocker Arm Ratio: 0.521 int./0.540 exh.
Lobe Separation (degrees): 110
 
#150 ·
Summit Racing Part Number: CCA-K11-450-8


UPC: 036584462316
Cam Style: Hydraulic roller tappet
Basic Operating RPM Range: 2,500-6,200
Intake Duration at 050 inch Lift: 232
Exhaust Duration at 050 inch Lift: 232
Duration at 050 inch Lift: 232 int./232 exh.
Advertised Intake Duration: 290
Advertised Exhaust Duration: 290
Advertised Duration: 290 int./290 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.578 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.578 in.
Valve Lift with Factory Rocker Arm Ratio: 0.578 int./0.578 exh.
Lobe Separation (degrees): 110
 
#153 ·
nice little Howards cam to look at?
121905-11 NA 286 286 233º 233º .600 .600 111 107 Hyd.
2500-6200 Rough idle, Hot Street. Good usable mid range power band. 9.5:1+ CR, 2500+ stall.
you might want a split duration cam if your exhaust ports are weak?
this cam would likely pull 5700 in a 496
If you get some flow numbers on the heads maybe use a bigger cam
 
#155 ·
it looks like i'll have to get new springs for both of those cams because the springs that came on the heads are rated to .600 according to the guy who built them but i can get the swapped out for free.
just need to get the correct springs.
im trying to find either of those cams in a full kit but i dont see it.
 
#156 ·
Do the cams you are looking at come with springs? If not make sure you get springs that are very close to the same lbs/inch as what's specified for the lifters/ cam. Solid rollers are more forgiving.
I'd try to get closer to .600 lift but not more duration. Or you could always run 1.8:1 rockers on the exhaust to get a little more lift. Too much duration sounds mean but will get lazy at low rpms.
Well. I ran at Topeka Friday night, but between operator malfunction, and a little greasy track I could only muster up an 11.80 @ 116 mph. Still a blast. Made 6 runs before I quit and watched the others.
 
#157 ·
ive found many comp cam kits that come with everything but the howards cams i cant find any.
if i can get a whole kit, i'll pay a bit more out of pocket but i'll get a little back when i swap out the springs and i'll have the peace of mind that everything is mated up.
sounds like you had some nice runs. i hope to make it to the local track this weekend.
 
#158 · (Edited)
Here is a mechanical cam kit with everything in it:
Product Line:COMP Cams Magnum Solid Roller Cam and Lifter Kits
Summit Racing Part Number:CCA-K11-692-8
Cam Style:Mechanical roller tappet
Basic Operating RPM Range:2,200-6,500
Intake Duration at 050 inch Lift:246
Exhaust Duration at 050 inch Lift:246
Duration at 050 inch Lift:246 int./246 exh.
Advertised Intake Duration:288
Advertised Exhaust Duration:288
Advertised Duration:288 int./288 exh.
Intake Valve Lift with Factory Rocker Arm Ratio:0.622 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio:0.622 in.
Valve Lift with Factory Rocker Arm Ratio:0.622 int./0.622 exh.
Lobe Separation (degrees):110
Intake Valve Lash:0.020 in.
Exhaust Valve Lash:0.020 in.
Grind Number:CB 288A-R10
Computer-Controlled Compatible:No
Lifters Included:Yes
Lifter Style:Mechanical roller
Valve Springs Included:Yes
Outside Diameter of Outer Spring (in):1.535 in.
Retainers Included:Yes
Locks Included:Yes
Valve Stem Seals Included:Yes
Timing Chain and Gears Included:Yes
Timing Chain Style:Double non-roller
 
#159 ·
Here is a hydraulic roller that is close to what Vinnie spec'd and is under 600 lift:

Product Line:COMP Cams Magnum Retrofit Camshafts
Summit Racing Part Number:CCA-11-450-8
Cam Style:Hydraulic roller tappet
Basic Operating RPM Range:2,500-6,200
Intake Duration at 050 inch Lift:232
Exhaust Duration at 050 inch Lift:232
Duration at 050 inch Lift:232 int./232 exh.
Advertised Intake Duration:290
Advertised Exhaust Duration:290
Advertised Duration:290 int./290 exh.
Intake Valve Lift with Factory Rocker Arm Ratio:0.578 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio:0.578 in.
Valve Lift with Factory Rocker Arm Ratio:0.578 int./0.578 exh.
 
#162 ·
picked up the block from the machinist today.
they told me it needs one sleeve and wouldnt know if it would bore to .060 cleanly until they just did it.
taking it back to the guy i bought it from and swapping it out if he has another one or getting a refund and the search continues....
 
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