BBC Build and Questions.

[chevybuldr]

Wow if it didnt touch that cylinder wall you got lucky. Mag for sure and if you are going to use the rods over again make sure they check that one to make sure its not bent.

[70stroker]

im gonna order forged rods and pistons, but ya i figured i would send the blok to the shop get in magged bored and line honed. It touched the cyclinder by just those scuffs pictured, which i think could be cleaned up after its a std bore now.

Would these heads do ok for my application with the blower and mostly street driven.

http://www.summitracing.com/parts/WR...1/?image=large

[ripdog28]

They would do fine but are a little small, those are similar to stock size. If you spend that much on them get the DART 308. I spent $1250 a pair.

[70stroker]

were did you get them? part number? I looked on summit, all darts stuff is 1000 each head..

[chevybuldr]

yea look at aluminum. Think you will be more happy with them.

[drag_72]

Originally Posted by ripdog28

OK, didnt know you were doing it your self. Your correct on the Forged rods and slugs and proper rings. Green 72 has a good cam just gotta have your valve springs set up for it. Stay away from Alum roller rockers, get some chrome molly ones. Some Super Comp headers should work fine. ALSO, I have heard some bad horror stories about plastic, see thru fuel filters, plastic melts when it gets hot and yours is pretty close to the engine. Get an alum or someother type of filter, i would hate to see that truck burned up.

there is nothing wrong with aluminum roller rockers? who the hell did you hear that from?

[ripdog28]

I have seen a 383 with a 8/71 on it pushing 15lbs of boost when it siezed up. the alum rockers had stress fractures in it. Would not happen to Chrome Molly and i know this is extreme.

[ulakovic22]

Yes, that is extreme and in the right conditions can probably be said about any part when put in a high stress environment like that. I also agree that a decent set of aluminum heads will be money well spent. With a blown setup you won't need a great set of heads because the air is going to be crammed in there.

[70stroker]

ok back on topic of advice for mybuild

[ripdog28]

what did you end up doing?

[70stroker]

Im still looking for a good bottom end kit for my app. I know my heads are gone i got them magnafluxed and one is cracked so i am looking for new heads. any ideas?

[ripdog28]

Aftermarket Dart/world if you want to stay under $2k, for a blower you dont need alum.

[70stroker]

are 336781 head castings good for my app?

[Alex1]

Originally Posted by 70stroker

are 336781 head castings good for my app?

Yes, those are excellent for your application - they're large ovals and can make serious power.

[70stroker]

Does anyone know what size stock valves were in the 336781 heads? Are they good with stock valve size or shine with larger valves? thanks

[Alex1]

They are something like 2.06 or something. It pays to have 2.25 intake valves put in.

[70stroker]

Ok guys i went and got the heads. they are 2 different castings but i talked the guy down to 80 bucks for the set so i took them. he said they both came off the same running motor. I dont really want to mismatch but what do you guys think? Or which heads are better so i can find another one of that kind?

first head

336781.....73-85...oval...OPEN...454, 118cc chamber, 256/114cc ports

second head

353049.....73-84...oval...OPEN...454, 122cc chamber, 255/119cc ports

[ProStreet71]

Originally Posted by ulakovic22

Yes, that is extreme and in the right conditions can probably be said about any part when put in a high stress environment like that. I also agree that a decent set of aluminum heads will be money well spent. With a blown setup you won't need a great set of heads because the air is going to be crammed in there.

I disagree with all do respect. Aluminum heads will help with heat dissapation and detonation allowing you to run more boost which makes more power.

[Alex1]

Originally Posted by ProStreet71

I disagree with all do respect. Aluminum heads will help with heat dissapation and detonation allowing you to run more boost which makes more power.

Agreed, however I don't think the plan is an all out blown motor here. I think it's just a small street blower on low boost.

781's and 049's a pretty much the same - I would prefer the same casting numbers for both heads though - but once worked over they would be pretty much the same.

[Twisted78SS]

From what I have read on several boards including here, in stock form it seems folks like the 781 as a "really good head" for a street motor, and they seem to like the 049 in a bit better. However, if you are going to massage them and move up to larger valves like 2.19 intakes etc... by the time you are done they will essentially be the same..

I gues it also goes back to the original intent for the motor and your application.

Best of luck, I would go and try to find another of each, then when you decide which way to go, you will have a spare set or good swap meet material

[70stroker]

Ok guys i found another 049 head so i am in business. but i got a few questions.

If i got .030. over on my bore that puts me at 4.280 I can not seem to find a head gasket thats close to that. the one i found is 4.380. would this work?

http://www.summitracing.com/parts/FPP-1071/

I talked to lunati the other day, got all the parts numbers for camshaft, lifters, valves springs. so i am good in that department.

However what do i need to be looking for for these heads? Bigger valves, what sizes? Also how do i need to figure out what size stems i need? Ill probably have stock size guides put back in unless someone sees a problem with that, again what is the stock I.D. of bbc guides?

thanks in advance guys

[70stroker]

bump anyone?

[70stroker]

[ripdog28]

Send the heads to the machine shop and have them set them up.

[70stroker]

heres some more parts that came in today.





and my blower powdercoated.