350 build

[1980c10]

It's time to begin my 350 build and I will have more than a few questions along the way. (On a budget)
I guess this is my before (current)

transmission is a sm465
I am planning on buying a parts truck for the engine, mounts, radiator, brackets and whatever else I may want for parts. then I will sell the left overs when I am done.
I am planning on having a local machine shop put the block together.
bored as needed,
flat top pistons, (about a 9.3:1 ratio)
mild cam with a decent range say 2-5500 rpms,
big valves in the heads and polished etc.
and assembled crank to heads and timing cover
price should be about 1400 for the machine shop work.<is this a fair price?
The truck is a sat night cruiser, don't need to race but want it respectable and okay to drive all weekend withiout filling the tank up 3 times.
I will get a set of headers to connect to my 2.5 inch magnaflow duals
I will also need an intake and carb, so I am looking for any advice on any of these areas. I will continue to post as I make progress.
btw here is a pic of the truck the engine will go in:


 

[bake74]

     That is a nice looking truck, you should be very happy with a 350's power.  Just ask your questions and you more than likely get more answer's than you want.  lol

[JDaniel]

Nice truck man.

[motion427]

Edelbrock Performer EPS and a 670 Holley Street Avenger would be a good setup.

[eventhorizon66]

big valves in the heads and polished etc.

Does this mean rebuilt stock heads with big valves?  It would be a MUCH better choice to rebuild a set of vortec heads.  For performance, this is the one thing you should stretch your budget for.

There is nothing wrong with a Q-jet.  You can buy a good 800 cfm core for $25 and rebuilt it.  If gas mileage and low speed torque are a concern, it is king of the carbs.

http://www.amazon.com/Rebuild-Modify-Rochester-Quadrajet-Carburetors/dp/1932494189/ref=sr_1_1?ie=UTF8&s=books&qid=1289167325&sr=8-1

http://www.cliffshighperformance.com/parts.html

[1980c10]

I have considered vortech heads, however I am going to save my money and keep it simple. throughout this whole project I have been keeping things on a tight budget while not skipping things either.  i should see plenty of HP for what I need it to do. some extra money will be spent on the machine work and on the pistons cam headers etc. I have a show winning truck and I'm not embarrassed to say how much it cost and want to keep it that way. However, vortech heads would be next on the list if I were to add more power for sure.

[1980c10]

Thinking about this carb listed as;
Chevy and GMC Trucks 8CYL ( 4BBL ROCHESTER ) QUADRAJET
1978-80
350 CID 400 CID
ROCHESTER QUADRAJET
http://www.guaranteedcarbs.com/cgi-bin/shopper.cgi?preadd=action&key=CTMHX3628
This could save me a lot of work.
I am thinking I would want at least 700 cfm not sure what this is.
what would be a good intake for this carb?
Single plane, dual plane, raised runners or stock?
bear in mind the other mods and I want to keep the powerband pretty wide as I will be using the sm465.

[1980c10]

also considering a high rise or the raised runner intake for appearance sake but only if it fits my application.

[eventhorizon66]

I've never heard of that guy.  If you want to save yourself the trouble of a rebuild SMI, The Carb Shop, and Cliff's High Performance are all very reputable Q-jet rebuilders.

I am thinking I would want at least 700 cfm not sure what this is.

CFM is the air flow of the carburetor in Cubic Feet per Minute.  You basically want as much cfm as you can get while still maintaining proper fuel atomization.  So for any carb there is a compromise to be made here.  For a Q-jet you can get a 750 cfm or 800 cfm model.  The Q-jet is designed with very small primary venturii and very efficient boosters.  This translates to big airflow (supports big horsepower) without giving up drivability around town.  Check out that book I posted earlier for good info on this carb including tuning it for max performance.

what would be a good intake for this carb?
Single plane, dual plane, raised runners or stock?
bear in mind the other mods and I want to keep the powerband pretty wide as I will be using the sm465.

For this mild engine, you want a dual plane, low rise intake like the Edelbrock 2101 or Weiand 8125.  A raised runner intake would only be compatible with raised runner cylinder heads and these are pretty much a race-only item.

[1980c10]

I meant I wasn't sure what the specific cfm of the specific carb was, i understand cfm in general.
I have had very good luck with a q-jet before. I am one who would rather be a little higher on the cfm than most most people. would I be alright with a dual plane hi-rise intake or should I stick with a low rise-what would be the difference performance wise? think I will stick with a q-jet on this one. btw-I haven't put an engine together in about ten years so all the help is really appreciated.

[eventhorizon66]

High rise dual planes have a straighter shot to the intake runners and a larger plenum volume under the carb.  This means they breathe better, but because of the larger plenum volume, they give up some low speed velocity.  On an engine with those heads, and a mild street cam it would cost you some low end torque, and maybe give a little more top end, when compared to a low rise dual plane.

You don't necessarily what to seek out high cfm above all else.  Fuel atomization goes downhill fast if you go too big and both power and drivability suffer.  In addition to this there is a point where power returns from increased cfm dimenish.  For an engine like this you would typically go for a 600-650 cfm Holley or Edelbrock carb for the best overall drivability.  But for the reasons I mentioned earlier no such compromise needs to be made for a Q-jet.  That's why it's such an excellent street carb.

[1980c10]

High rise dual planes have a straighter shot to the intake runners and a larger plenum volume under the carb.  This means they breathe better, but because of the larger plenum volume, they give up some low speed velocity.  On an engine with those heads, and a mild street cam it would cost you some low end torque, and maybe give a little more top end, when compared to a low rise dual plane.

wouldn't the fact that it is a dual plane intake kind balance out the higher plenum volume?
if so-
with that in mind I feel like maybe the high rise isn't a bad idea as I won't be running an auto trans(less weight to get moving) and I can rev it a little more to get the air moving. I do also feel pretty safe going with a q-jet.

The last engine I put together was pretty much this same set up heads, compression, headers, cam, four speed etc, I used a high rise intake plus adapter with a holley 600 dual feed in a 2wd swb s10.  everyone said too much carb but I already had so I tried it. throttle response from take off was impressive, I always sarted in 3rd gear(geared pretty low), only problem with this truck was traction, could not believe what this v6 could do. carb seemed to be a perfect match. From that experience I would not want be below 700 cfm with a 350.
However that was not a q-jet on a high rise, kind of wondering if the q-jet would work as well.

btw what would be a good set of headers to get for this truck, I want something that won't rust right away and is budget friendly.
Thanks again for the help.

[eventhorizon66]

wouldn't the fact that it is a dual plane intake kind balance out the higher plenum volume?

Compared to a high rise single plane like the Victor Jr, yes.  But compared to a low rise dual plane like the Edelbrock 2101, it should make less torque at low rpms.  I'm not saying it would be a dog, but it probably wouldn't ideal either.  If you don't mind giving up a little low end for some top end, go for it, but I'd be running a low rise.  Also if high performance is a serious goal, I'll reinterate that you are probably using the wrong heads.

However that was not a q-jet on a high rise, kind of wondering if the q-jet would work as well.

Q-jets can make power.  http://www.pontiacstreetperformance.com/psp/rebuild455jh99.html

btw what would be a good set of headers to get for this truck, I want something that won't rust right away and is budget friendly.

Here is a set of headers I see recommended quite often by our resident expert VileZambonie.  I have no experince with them but they seem nice for the money.
http://www.summitracing.com/search/?keyword=31500FLT&dds=1

[1980c10]

-Those headers and the edelbrock 2101 both look really nice for the money and a q-jet. maybe down the road I will get some different heads but I need to keep the budget under control for now.

- If I did the vortech heads now I would probably have to give something up for them-don't really know where I could give something up at this point. I had also considered a stock 350-but I knew I wouldn't be as happy with the final product so this puts me somewhere in the middle-I just really want a dependable solid performing engine and the inline 250 sucks, Ive been getting poor mpg without the fun and I've already got about 10k in this truck (worth it btw) trying to keep this total under 15k by spring if I can.

-I am hoping to see 300-350 hp.
 

[eventhorizon66]

That's OK, you can definitely hit 300-350hp with those heads, but it won't make as much torque as the vortec heads on a combination making the same 300-350hp.  I still think you'll have an enjoyable engine so long as you keep the cam mild and do a good job tuning the Q-jet.  And regardless of what you do with the engine, you have mighty fine looking truck.

Good luck and have fun.