Help with 350 build

[Senck243]

I have a 350 tbi on a stand in my garage. I am planning on building it and swapping into my 84 k10 with a sm465 which currently had a 305. My questions are should I use the 350 heads or put the 305 heads on I am on a tight budget and want reliable/power but just as a plow and work horse. Thanks for the help

[DustyRusty]

Personally, I would keep the 350 heads on it and go.  I'm not sure you would really gain anything w/ the 305 heads.  My $.02.

[TexasRed]

305 heads will put you in premium gas range. Plus they run outta flow pretty quick, which probably isn't a concern for you for towing. The 350 heads will be your best option in my opinion.

[codyC10kid]

id go the the 350 way....( that's what I'm doing) i also have a 95 TBI 350 i just put dome pistons to raise the comp. ratio...like others said the 305 heads will raise compression But they don't flow well..the 350 heads will some what lower your compression but they flow better...So my build is a 350 with stock 350 heads (port and polished) dome hypertectic pistons (bored.030 over) comp cams extreme 4x4 cam kit...my Compression ratio is 10.6:1...Also I'm swapping the tbi for edelbrock Performer EPS intake and 600cfm edelbrock carb

[Senck243]

Your build is similar to what I am going for. I am going to try and not bore it that much tho. I am mainly driving around town and plowing

[codyC10kid]

Your build is similar to what I am going for. I am going to try and not bore it that much tho. I am mainly driving around town and plowing

boring .030 over isn't that much...In fact .030 is min. and if your crazy you could go a max of .060 over,Anyone would recommend boring .030 over if your cylinders have queit abit of ware,I got my Block back yesterday from the machine shop,spent a lil over $300 to get it bored cleaned cam bearings installed and frost plugs put in...I'm ready for bearings pistons etc.,I already have the intake carb crank rods covers starter,Spend about $1600 on the bearings cam kit pistons gaskets Electric fuel system and I'm ready to rock...So for around $2000 i can have a good running 350

[Senck243]

I agree that .030 over isn't crazy but I would like to bore as little as possible so I have somewhere to go God forbid something happens again

[codyC10kid]

I agree that .030 over isn't crazy but I would like to bore as little as possible so I have somewhere to go God forbid something happens again

If your gunna bore it to clean the cylinders up..i do believe .030 is min. (i don't think they sell pistons for like 4.010 OR 4.020) i think they just have .030 .040 .060 aftermarket pistons

[Avidyn]

They do make them in other sizes. But, you're going pay for them. There are companies that will make them custom for you.

[codyC10kid]

They do make them in other sizes. But, you're going pay for them. There are companies that will make them custom for you.

Hey thanks for the info..im 19 learning on my own so far i have all the parts for 2 motors in my room Lol yeah not put together yet my 400+hp 355 motor needs a fuel tank and pump,alternator,tranny then its getting built,my 4x4 355 i need a set of gaskets and pistons,then im building that one with in a week or 2

[Jason S]

Are you rebuilding the 350 heads (valve job, guides, etc.)?

The TBI heads are okay, there are much better heads available. Based on your options and desired performance, stick with the 350 heads.  You can swap better heads on later (e.g. Vortec).   

Are you going to use the original intake or go with an aftermarket intake?  The center bolt holes on the TBI heads are at a different angle than your '84 heads.  You'll need to modify your current intake manifold or use an aftermarket (preferable) intake manifold. 

[78 Chevyrado]

I can't say if this will work out for you...  but this worked beautifully for me.

I swapped a 1973 400sb into my 87, and having the 1973 heads but needing the 87 intake, I wouldn't have use of the center bolts.  So I took the 87 intake, filled the bolt holes with epoxy, then filed the epoxy down on the machined face, and only used the bolts at the outside to bolt the 87 intake to the 73 heads.  I said what have I got to lose, so I tried it.  It worked for me, I put 60k miles on it and never had one problem.  It may not work, and I know it's a hack, but it worked for me totally.  Back then though, there werent any TBI manifolds available, except stock, so if it hadn't worked, Id have had to get a 4bbl intake to fit 73 heads, and use an adapter for tbi to 4bbl.  not ideal, but I never had to find it out. 

[jaredts]

I would try to find some different heads.  TBI heads don't flow well, and would need some adaption to work for you anyway as mentioned.  The 305 heads aren't a good option either.

[Senck243]

Is just simply honing the cylinders an option if the walls are in good shape?

[jaredts]

If you want zero risk and a perfect job then you need to get it bored and honed.  If you have a rebuild book it usually explains how to check the cylinders with a telescoping gage.  If they're within a couple thousandths both ways up and down the bore and has no scores you can get away with it.