6SpdLT1Z

I was hoping some members could chime in on budgeting for a 355 build.

I have 156k on my bolt-on LT1 and am planning on building a 355 in the near future. Part of me is tempted to look at people parting out LT1s for builds as I know I can save some $$$/time going that route but I know it can be risky if it wasn't built right.

How much do you guys suggest to be prepared to spend for a 355 build? I don't PLAN on doing any head work initially, and I'd be looking at a mild 226/234 .566/.566 @ 110 cam or comparable. For the purposes of my build I'd like to find a short block used and go through it using a stock crank, but freshening up quite a bit of it. Plan on finding a 4 bolt block or running a studded 2-bolt / splayed 4-bolt. Not planning on putting much more than 400-450rwhp through this engine. I'd be building the engine separately to minimize downtime on the car.

Should I be planning on upgrading the transmission/rear with the build? I realize that the more it is beat on with the new power levels the more likely it'll be to blow up the the transmission/rear. How many people didn't upgrade their transmission/rear and how have they handled it?

• 156k stock longblock, heads are very clean
• bolt-ons (52mm tb, pacesetter lt, 3" full exhaust)
• stock transmission with newer factory replacement clutch
• stock rear end with 3.42, no whines, fresher fluids

Thanks all, feel free to PM me if you don't feel comfortable posting about financials publicly.

RamAir95TA

The term "355 build" unfortunately many people associate with a performance-type build. The fact of the matter is "355" just means displacement. There is no associated expected horsepower or torque output, main requirements or what rear/transmission is necessary. So first thing you need to do is understand that a 355 is a stock bottom end with 5 extra cubes - that's it. And for all intents and purposes a stock bottom end 350 with the same heads/cam/whatever as a 355 will put down the same power within 1% of the 355.

For a mild build like you mentioned there is absolutely no need to go to a 4 bolt main. The stock 2-bolt is quite strong and for your power output it would be fruitless to spend time and money beefing it up (I've seen stock bottom ends run well in excess of 700+HP, do a search for LT1 used vtec).

Stock 150k motors take that camshaft all day long without a problem.

Having to upgrade the transmission/rearend will be dictated by your goals for the car. If you're going to be drag racing alot then yes of course a stronger rearend is warranted but if you're just looking for a street cruiser then a 10-bolt will suffice. The stock T56, depending on its condition, may need some refreshment but a good clutch should really be all you need for the time being.

6SpdLT1Z

Sorry maybe I should've specified that I HAVE helped build a 355, just not using my wallet. So I do realize that I would need new pistons (I might do a ~ .5 bump in compression) I plan on re-ringing the pistons, new cam bearings, etc. I realize that a 5 cubic inch increase (.30 over) isn't going to cause me to all of a sudden need to upgrade my rear, transmission, driveshaft. I expect to be looking at 350-375 rwhp cam only and a little over 400 with heads.

To save money, as of right now I plan on reusing the crank, connecting rods, and other things that should be stout enough. Just because I used the word "budget" doesn't mean I'm trying to do this for $300.

You can put that camshaft in a 250k stock motor and it'll take it. I'd prefer to take it reliably and not spin a rod, cam bearing, etc.

Good point as I didn't mention that. It'd be a street/stip car that wouldn't see much time on the drag strip. If anything I'd prefer to auto-x/road race it so I'll look to improve oiling with the upgrade. I'd plan on bumping the clutch up to a LT4 or Spec II probably.

RamAir95TA

That clears some stuff up. If I were building a reliable budget 355 bottom end I'd go this route:

Stock reconditioned crank, stock reconditioned rods with ARP bolts, a good forged budget piston (SRP, Mahle, etc.). All on the stock 2-bolt mains. That should EASILY hold your desired power and then some.

Don't bother upgrading the oil system either. A stock pump with a high pressure spring will be more than enough. If you do insist on upgrading the pump I suggest the Melling 10554 with the hardened driveshaft.

All in all the bottom end shouldn't cost you any more than $1500 (assuming you pull the motor apart and bring it to the machine shop yourself).