BBC Build and Questions.

[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.

[Twisted78SS]

I found the article mentioned comparing a mini blower to an 871

http://www.chevyhiperformance.com/te...ine/index.html

It's a good read, and might provide some insight on parts selection and outcome.

Makes me want to get back on my project quickly..

[70stroker]

quick question guys, I line honed by block. Now i have never had to do this with any of my blocks. My question is how do i order the correct bearings? I mean a .030 oversize bearing adds material on the crank side to make up for a ground crank. What about if you take metal off the other side? thanks

[Captainfab]

Line honing doesn't change the outer diameter of the bearings needed. A couple of things you will have to get different since the block is line honed is a specific rear main seal (not positive on BB, I know sb does) and a slightly shorter timing chain ( typically .005 or .010).

[70stroker]

well actually they were not installed before, I really wanted new bolts or studs vs the stock ones.

So if you guys see it a problem then i either send it back to the machine shop to have it honed again. I rather be safe then sorry.

Could i just but arp bolts and be ok? Or have to have it checked again?

Dont take this as a bad attitude guys. Actually thats why i posted here hoping someone would catch anything out of place. I appreciate the heads up before i go any further. You guys are great.

So what would you guys do? Like i said the bolts that was line honed with were stock as far as i know... I dont really trust them with a blower sittin on top... or would i be ok?

Just let me know what you guys think.

Thanks again.

[Captainfab]

Typically anytime you change your main cap bolts to either new bolts or studs you should have the mains line honed. New fasteners will change the distortion they create on the main bores. So if you were not wanting to reuse the stock main bolts, the studs should have been installed prior to line honing. I'll let one of the experts recommend what to do now.

[chevybuldr]

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

[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.

[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]

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]

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

[MylilBowTie]

Did you have the machine work done already? If so isnt it a bad idea to install main studs now?

[Captainfab]

Hopefully those studs were installed for the linehoning process.......