(kinda long, sorry
I went to a shop today that said they
would do my head,cam, and intake swap for $150
Plus misc. parts.
However they tried to "scare" me into
forging my bottom end, which I have
NO intentions of doing. I was wondering
AT WHAT POINT(horsepower) IS IT NECESSARY TO REBUILD
THE BOTTOM END?

btw: I didn't tell them it was a 305 either so
the "Why bother with a 305, get a 350" doesn't suffice for an
answer here!!

 

The 305 is probably a stronger bottom end than a similar 350. Same stroke, same rod length, the 305 has a smaller piston (lighter) and less surface area so even less piston skirt "slapping" so I'd say it's probably good for ~400hp. That's as far as I would go with the stock bottom end on the 305 with or without a power adder. I don't expect to test my limits with my engine. After a cam swap I'm going to try and stay below 430hp. Cast pistons will expand and too much hp (a lot of fuel and oxygen combusting) will push the limits too close for comfort. Forged pistons are actually barreled in most cases and aren't as big as a cast piston because they are designed to be abused. It's a long story and requires pages to explain everything so don't do shoot for more than 450hp on a stock bottom end Lo3!

 

what kind of shop would install all that for just 150

 

That's what I was thinking when the said it!
It's a performance retailer that has a machine shop in the back.
I think they're gonna try to add on miscellaneous costs to up
their come up.
I would do it myself but,
I'm 19 in college with no tools, no garage, and no experience!!!

 

That didn't stop me from doing an engine swap . I was 19, no tools (borrowed a SMALL tool box), no garage (used a neighbors COLD barn), and zero experience!!! That's just more of a reason to do it yourself either during spring break or the summer. It's not like any of this is rocket science, no formulas, just a torque wrench and common sence like don't let ANYTHING fall into the engine. I dropped a washer into my intake port of my engine and had to fish it out with a coat hanger! The lesson learned is to use duct tape or paper towels where applicable.

 

boy have i got a story... i borrowed my mechanic's cherry picker and took the engine out in my driveway. the engine i built in my garage with a torque wrench, sockets/racthet, dremel w/ wire wheel, and a haynew manual. i put it in in my driveway and had it running in about 3 days... it was a weekend where it was like 60 + degrees here.

 

i got little experience but i am just going to kinda start the cam swap spring break and see how it goes. of course i have a garage and tools(my dads). the only thing i dont know how to do is degree in a cam, and if it is really necessary for me.

 

I didn't degree my cam when I installed it. Just lately I see people speculating on if its necesary to degree a LT1 cam. I wounder how many cams GM degreed when they installed them new in LT1 motors.

 

gota make sure, sometimes cams have degrees allready built into them so they should be installed straight up.........not sure about lt1 cam so i cant say on that............

 

As far as your 305 being safe - theres 2 things 2 keep in mind.

1) I've worked at a machine shop for 2 years - the 305 and 350 share the SAME EXACT (SSSAAAAAAAAAAAAAAAAAME!) bottom end. The ID numbers on the cranks and the rods are completely interchangeable - so as far as that goes - the 305 will survive just as well as a 350, maybe a little better w/o the extra weight from the 350 pistons. As long as you don't rev the motor past its redline (much! a stock crank is good for about 6,000 rpm w/a good rotating assy.) it'll live - besides, cast pistons are good to around 300hp anyway - and its not like any 305 will be hysterically above THAT. Keep in mind though that if you "forge" your bottom end (like these imbecils suggested) you'd be adding heavier pistons anyway! The only way that would make sense is if you balanced the bottom end - which i'm SURE they don't have the facilities for (can you hear the "cha-ching" in the background?). My suggestion is either do it yourself or get some other estimates. $150 is about 3 hours labor and that's total crap for all that work - look around so you don't get cheated man. Some shops are real hackers if you're not careful - make sure the parts you give them end up in your car! lol. And one last thing - if you're gonna pull the whole motor - replace the block and build a 350! you've already got 2/3 of the parts!

2) - well, i kinda put #2 in #1. lol. You get my idea.

TP