Planning summer small block build

[Obwonkonobe]

I just dropped a 700r4 into my 78 c10, and now that its working like a dream(thank you to all that helped), I'd like to turn my attention to my motor.

I've got a reman 350 that has smogger heads and 15 psi of oil pressure when hot, so I figure while its ok to daily, there's room for improvement.

I've been looking at doing a sbc 400 with vortec heads. I figure I can use my 350 accessories, distributor, and carb and drill steam holes myself. Im on a tight budget but if I keep the stock rotating assembly I think the 64cc vortecs will be enough to bump the compression. I may put a cam in it but it'll come down to cost, other than having it externally balanced is there anything else I need to think about?

 

[Dutch Rutter]

I'm actually planning on doing the same thing but with a second 350 motor that is already pretty hopped up but will get refreshed and probably change the cam, intake and a few other things.

One of the bigger expenses I figured on doing was getting my rotating assembly balanced by a shop. Are you planning on picking up a crate, pre-built motor or pulling and working over your current one?

You are correct you can use all of the accessories, dizzy, and even carb assuming your current carb is enough for the 400.

 

[Obwonkonobe]

I'm actually planning on doing the same thing but with a second 350 motor that is already pretty hopped up but will get refreshed and probably change the cam, intake and a few other things.

One of the bigger expenses I figured on doing was getting my rotating assembly balanced by a shop. Are you planning on picking up a crate, pre-built motor or pulling and working over your current one?

You are correct you can use all of the accessories, dizzy, and even carb assuming your current carb is enough for the 400.

I figure il just haunt craigslist and the local yards until I find a 400 block and assembly. Hopefully I can resuse the stock assembly, and MAYBE try to ballance it myself. Im in no rush since the 350 in the truck is still running reliably. The name of the game for me is cheap, and since I have time I figure I may get a little adventurous

 

[Dutch Rutter]

Gotcha. Always figure on all new gaskets and seals, probably bearings, oil pump, water pump, rings, a timing set while your in there. These are mainly the things I've figured I'll be doing for a general refresh. Luckily enough parts for any and all sbc are on the cheap side.

If you can try to find a block with a factory roller cam. That would be a better starting build point then the flat tappets. Here is something I read through which might help out.

http://www.hotrod.com/articles/hrdp-0905-small-block-chevy-build/

I'm not too sure how vital it is for the rotating assembly to be balanced, I've built a 350 motor without having it done and ended up pulling it after 30k miles to replace a main bearing and have the crank trued back up. I have not yet gotten one balanced that I built. I do think it will run smoother with less fatigue though, hopefully someone else can speak to that.

 

[Obwonkonobe]

Gotcha. Always figure on all new gaskets and seals, probably bearings, oil pump, water pump, rings, a timing set while your in there. These are mainly the things I've figured I'll be doing for a general refresh. Luckily enough parts for any and all sbc are on the cheap side.

If you can try to find a block with a factory roller cam. That would be a better starting build point then the flat tappets. Here is something I read through which might help out.

http://www.hotrod.com/articles/hrdp-0905-small-block-chevy-build/

I'm not too sure how vital it is for the rotating assembly to be balanced, I've built a 350 motor without having it done and ended up pulling it after 30k miles to replace a main bearing and have the crank trued back up. I have not yet gotten one balanced that I built. I do think it will run smoother with less fatigue though, hopefully someone else can speak to that.

Nice read, I'll have to find a good machine shop here in az first and price stuff out, and find a short block lol

 

[Iowan]

434 Stroker, 10.0:1-11.5:1, take the timing down a bit so you can run 91 or 93. This isn't really a serious option for a DD, but a 400 with a 9.0:1 or 9.5:1 would be really great. Now do remember that the 400s have steam holes because of the Siamese cylinder bores and your Vortec heads will have to be drilled for that. You also may want to do screw in rocker studs and roller rockers. I'm not sure if you have headers but they are a worthy investment for a 400 In my opinion. Whats your gear ratio? and do you have overdrive? I ran a 2.73 with a 400 and 235/75/R15s and got about 17-20 MPG if that's what you're interested in.

 

[Obwonkonobe]

434 Stroker, 10.0:1-11.5:1, take the timing down a bit so you can run 91 or 93. This isn't really a serious option for a DD, but a 400 with a 9.0:1 or 9.5:1 would be really great. Now do remember that the 400s have steam holes because of the Siamese cylinder bores and your Vortec heads will have to be drilled for that. You also may want to do screw in rocker studs and roller rockers. I'm not sure if you have headers but they are a worthy investment for a 400 In my opinion. Whats your gear ratio? and do you have overdrive? I ran a 2.73 with a 400 and 235/75/R15s and got about 17-20 MPG if that's what you're interested in.

High teens! Im very interested. I have 3.08s with 31 inch tires, and a 700r4. And il be sure to drill those steam holes. Headers are the last thing I want to do to the truck before I ditch the 350 lol

 

[Iowan]

High teens! Im very interested. I have 3.08s with 31 inch tires, and a 700r4. And il be sure to drill those steam holes. Headers are the last thing I want to do to the truck before I ditch the 350 lol

Engine Masters did a Header size test, the 400 used a 1 3/4 to greatest effectiveness. You do have an overdrive trans as well, @55 you should be at a 1285 rpm, that should be really decent for MPG. I'm not sure if you're into loud but an exhaust can make a lot of difference. If you do 'cam it' roller lifters are the safer (IMHO) but flat tappet works too. This is subject to whatever cam is in the engine is but if you wanted to you could 1.6 rockers for a little more lift, the problem is if the cam is much past .450-.480 it could pull out the studs.

 

[Obwonkonobe]

Engine Masters did a Header size test, the 400 used a 1 3/4 to greatest effectiveness. You do have an overdrive trans as well, @55 you should be at a 1285 rpm, that should be really decent for MPG. I'm not sure if you're into loud but an exhaust can make a lot of difference. If you do 'cam it' roller lifters are the safer (IMHO) but flat tappet works too. This is subject to whatever cam is in the engine is but if you wanted to you could 1.6 rockers for a little more lift, the problem is if the cam is much past .450-.480 it could pull out the studs.

I have 2.5 inch dual exhaust coming off my manifolds, so if I do headers I should be good there. And I like that rpm very much. 400s were made from 70 to 80 so I'm not sure if they have the bosses for a roller cam, but if it does il look into it. I think if i don't skimp on oil i should be ok though, and I don't plan on going with a radical cam, but I'm no expert on cams so im not sure what il go with yet

 

[436'd skylark]

No factory roller cam 400s. You'll have a nice running engine with the vortec heads. A couple things to consider though. Out of the box the vortech heads need work to run a high lift cam. You can get bee hive springs to help some.

400s used a short rod from the factory. Building a 6" rod 400 will be a very torquey motor.

As far as the at home balance job you won't accomplish much really. Yeah you can weight match the pistons and rods but that is only half the job. The counter weights on the crank are matched to the pistons and rods. Its the full rotating weight of the rod plus half the reciprocating weight. From there you add or remove weight to the crank. Doing half the job doesn't gain you anything.

 

[Obwonkonobe]

No factory roller cam 400s. You'll have a nice running engine with the vortec heads. A couple things to consider though. Out of the box the vortech heads need work to run a high lift cam. You can get bee hive springs to help some.

400s used a short rod from the factory. Building a 6" rod 400 will be a very torquey motor.

As far as the at home balance job you won't accomplish much really. Yeah you can weight match the pistons and rods but that is only half the job. The counter weights on the crank are matched to the pistons and rods. Its the full rotating weight of the rod plus half the reciprocating weight. From there you add or remove weight to the crank. Doing half the job doesn't gain you anything.

Ah that makes more sense, would I get a bigger displacement with 6" rods?

 

[Iowan]

I have 2.5 inch dual exhaust coming off my manifolds, so if I do headers I should be good there. And I like that rpm very much. 400s were made from 70 to 80 so I'm not sure if they have the bosses for a roller cam, but if it does il look into it. I think if i don't skimp on oil i should be ok though, and I don't plan on going with a radical cam, but I'm no expert on cams so im not sure what il go with yet

You should get bigger displacement and little more compression. Retro roller cams are going to be the roller cam option. Look at the Comp Cams Xtreme 4x4 cams, something from about 600-1000 RPM maybe 1200, http://www.camquest.com/.
http://www.hotrod.com/articles/ccrp-1112-406ci-small-block-chevy/.

 

[Obwonkonobe]

You should get bigger displacement and little more compression. Retro roller cams are going to be the roller cam option. Look at the Comp Cams Xtreme 4x4 cams, something from about 600-1000 RPM maybe 1200, http://www.camquest.com/.
http://www.hotrod.com/articles/ccrp-1112-406ci-small-block-chevy/.

Il decide on those rods once I find my short block. Defiantly something to think a out but I don't think il really need it for what il be using the truck for. Its just a cruiser. I checked out the "retro roller cam" and its not too bad a price! Would those lifters work even without the spider web thing over them like in a roller block?

 

[4WDKC]

You should go up to atleat a 5.7 rod, one of the reason the 400 has such a bad rep is the short stroke puts a lot of side load on the cylinder walls, longer rods help reduce this. Problem with 6.0 rods is dont you have to buy a smaller than normal base circle cam adding additional cost?

for the cost of checking the vortec heads, valve job and screw in studs you will be about the cost of a new set of aftermarket vortec heads. I just swapped my truck to vortecs and a cam..wish I had just put the money in my 454 instead. Prices as I encoutered

vortec heads $100
needing addition non cracked head $35
magna flux, valve job, new seals, springs & setup $400
Used intake manifold $100
gaskets $75
cam & lifters $120
springs again because machine shop ones broke. $30
timing chain $30

And you will need new rings, bearings, seals, hone... either save and do it right or dont do it at all.

 

[Iowan]

Il decide on those rods once I find my short block. Defiantly something to think a out but I don't think il really need it for what il be using the truck for. Its just a cruiser. I checked out the "retro roller cam" and its not too bad a price! Would those lifters work even without the spider web thing over them like in a roller block?

I do believe you will have to use those link bars so it doesn't turn on the cam lobe. Keep in mind that if you do cam it you may want to look at a higher stall converter.

You should go up to atleat a 5.7 rod, one of the reason the 400 has such a bad rep is the short stroke puts a lot of side load on the cylinder walls, longer rods help reduce this. Problem with 6.0 rods is dont you have to buy a smaller than normal base circle cam adding additional cost?

for the cost of checking the vortec heads, valve job and screw in studs you will be about the cost of a new set of aftermarket vortec heads. I just swapped my truck to vortecs and a cam..wish I had just put the money in my 454 instead. Prices as I encoutered

vortec heads $100
needing addition non cracked head $35
magna flux, valve job, new seals, springs & setup $400
Used intake manifold $100
gaskets $75
cam & lifters $120
springs again because machine shop ones broke. $30
timing chain $30

And you will need new rings, bearings, seals, hone... either save and do it right or dont do it at all.

X2
I found some eBay heads, yes Ebay. before you say you cant buy good quality parts from there hear me out, they are $310 they have a 2.02 int and a 1.6 ext. they are not assembled so you go buy the springs, retainers, guides, valves, push rod etc and you can have some really nice heads. https://www.ebay.com/itm/2x-ALUMINU...693638?hash=item4b324164c6:g:bQkAAOSwY~1aRWPF I have heard good things. No guarantee just what I have heard.my cam suggestions:

1. http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=164&sb=2 - It's a mild cam and does sound too lopey but delivers a lot of power down low.
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2. http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=155&sb=2 - Slightly more mild but should give slight power increase
3. http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=156&sb=2 - Should sound like number 1, has little more lift.
4. http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=95&sb=2 - It's a flat tappet but is still really good.
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