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Building 350 Sbc - 2 Bolt Main

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I have a 350 small block with a 2 bolt main that I am trying to build to swap into my 93' sonoma. I am wanting to push 400-500 hp. I am by no means experienced, but I want to learn. Just looking for any advice on what parts/ things I need to get or do. my budget is around $2200.
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So we’re talking about a V8 conversion to an S15 platform. Is 2200 just to build an engine or for the whole V8 conversion?

For any decent engine life span the 2 bolt main is not suitable for 500 hp beyond visiting it once or twice for a couple seconds. 400 is a more realistic goal on a 350 and the 2 bolt mains will tolerate it for a while.

To do 400 takes modern heads as does 500 starting at the Vortec which still requires substantial modification to the upper valve guides for high lift clearance and the installation of screw in rocker studs, as well as a substantial cam and a compression ratio of 9.5 or more.

Your far better off to start with a 4 bolt block, when you consider the need for a modern chambered head, high rise intake, big 4barrel carb, semi exotic cam with lifters and valve springs, replacement connecting rods, porting the heads a good possibility if factory Vortecs, balancing the crank, improved ignition, revised fuel delivery from the S15’s low pressure electric injection pump. Beefing or replacing the transmission, replacing engine mounts, cooling system a real pain to fit what the V8 needs, drive shaft modification, custom exhaust system, etc. the budget of 2200 dollars unless you have a lot of tools and a machine shop at your disposal looks quite inadequate.

Bogie
 

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basic sbc overhaul kit from Northern Auto Parts (Watch your piston height/head casket and cyl head chamber cc).
S10-V8 Conversion kit
Engine add ons: RV Cam from NA, buy a set of Comp DLC coated lifters, find a used Performer EPS intake, good quality GM HEI distributor and an E-core coil; Some sort of used 650cfm carb.

Any money left? C-clip eliminators?

400hp? No. But it'll get you going, it'll be ridiculously fun to drive. THEN evaluate your project. Brakes, suspension? Stronger axle? Or save up for your dream 383 SBC? Or decide that S-15's arent your style and move on to something else.
 

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I’m under my S15 tonight chasing transmission oil leak and looking at how tight the V8 install is and it is an exercise. I used Mike Knell’s method from Jags That Run as described in his two books Chevrolet TPI & TBI Engine Swapping and Chevrolet S-10 Truck V8 Conversion Manual, two reads I highly recommend before you spend real money. Even if you decide to use a commercial kit these two books are a gold mine on getting a Gen I or II SBC into the S-10 and S-15 chassis.

My own headache is finding the source of why my 700R4 turns the pavement red with ATF but only sometimes. So I expected that the Lokar dipstick that I installed without sealer on its O ring, even I forget steps, was the cause. The assumption being the converter fill valve leaks when the truck is not in use and floods the pan which then leaks past the O ring. The lesson possibility is the converter shaft seal occasionally leaks. So I spent the day checking and rechecking to find the inside of the bell housing and torque converter is clean and dry. The vent is clean and dry. The hoses going to the cooler are clean and dry at their trans fittings but filthy with red oily crud where the out line to the cooler wraps around the 4th apply servo to find space further back for a tee where the ATF temp gauge sender is located. The return line from the sender runs along the pan rail to get into the engine room and to the cooler up front. It joins the return line where these are stuffed behind a heat shield protecting them from the right side header tubes. This area along the pan rail is swimming in bright red ATF. My expectation is the three pan bolts that also secure this heat shield are leaking and when stopped for a while the converter drains back flooding the pan higher than the pan then the ATF oozes out. I’ll see what can be done and put it back together tonight.


Bogie
 

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Discussion Starter · #8 ·
Thank you all for your help, I realize now that with it only being a 2 bolt main, I don’t want to be trying to make to much power from it. Does anyone have any good reccomendations on a decent set of heads that won’t break the bank?
 

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Depends on your skill level, are you looking for assembled or bare heads n put together with your own parts? Lots of the modern cheaper heads have a good design, I'd avoid procomp/speedmaster they are a very old design. Rebuilding vortecs/oem heads cost about the same or close enough as some of the cheaper aftermarket.

More details like your plans/use will get you better advise on a head size or other parts.
 

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You'll also need to address the 7.5" rear axle. The first time it sees traction and 400 hp, it's scrap.

Not being a poopy head, but 500 hp from a 350 is remarkably expensive, and it will be incredibly tiring to run on the street. It will also require thousand$ in supporting modifications: Very expensive transmission upgrades, torque converter, u-joints, rear axle, gears, cooling system, fuel system... deeeeep pockets.
 

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You'll also need to address the 7.5" rear axle. The first time it sees traction and 400 hp, it's scrap.
Friend of mine ran a 7.5 with a mini spool & slicks in a 80's monte with a 355 making 400ish at 3500rpm launches, never broke it. But it was just street racing or a poor prep track and not a good prep sticky surface.
 

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Boot I use 2x intake CFM to determine peak power in a V-8 configuration.
heads posted 259 cfm intake side with good exhaust ratio.
I rounded to 250 cfm x 2 so 475/500 is a good estimate considering street engines that might be under carbed on a dual plane intake and good possibility of not running a solid cam.
For my personal engines I consider 2.2 hp per intake CFM with correct parts to fully use all the air (RPM related)
 

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2 schools of thought here.
1 is use factory iron heads; 186s or something. No needing to worry about longer valves, or thicker head gaskets. Throw some roller tipped rockers at it and let it rock. 375hp or so is realistic and not exactly a slouch for your first engine build. Its going to be fun in that S-dime no matter what.

If you go with aftermarket heads, probably aluminum, and this brings in another layer of head gaskets, squish/quench and then we get to go through valve train geometry. Insurmountable? No. But there is the chance that you'll need to dismantle the top end a couple times as you learn what works and what doesnt.

Most of us here ended up cutting our teeth with simple factory stuff so the learning curve with aftermarket kit was a bit less steep.

Yes ill get poo-poo'd that this stuff isn't hard and anyone can do it. I don't know your skills or comfort level so I'm simply starting the conversation.

If it were me, I'd probably just do a stock rebuild with an RV cam. If anything, some Vortecs that were already checked for cracks. But remember thats a vortec specific intake and valve covers.
 
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