ws6transam

With tighter bore, the valve opens simply to have most of the valve facing a steel wall. Since the incoming air must bend and twist around the valve head, the closer the cylinder wall is to the valve face , the harder it is for the incoming air to squeeze past. The shrouding limits your air flow to the point where a bigger valve doesn't help airflow, it only hurts air flow velocity. That's why its not uncommon to see performance 305 builders grind a bevel on one side of the cylinder closest to the intake valve in an attempt to reduce the shrouding effects. It's a dangerous mod, though because if one grinds too much, they might strike the water jacket and effectively ruin the whole engine block.

92RS305#2

thankx for the confidence, lol. i mean it'd be easy to go out and get a 350 block but i can always do that once i get out of school. whats so wrong with building up a 305 block? i bore, stroke, and cam it and add some better internals as well as port/polish intake. do the exhaust and rearend and drive it for a while, then when i get tired i put in a new engine and drag race it. by then i'll have a truck or something. in the meantime if i get tired of the 305 i install TPI and supercharge it (or carb and supercharge it). maybe i'll change my mind in a few months but for now, until i find a $50 350 block in good condition, ima gonna stick with that plan.

ws6transam

92RS305, it sounds like a good plan. However, might I suggest you keep the current crankshaft? Put the money into something else, and spend your time optimizing the cylinder heads. The 305 crank is as strong as a 350 crank, and the 305 rods are forged steel 5.7 rods, just like the 350's. Instead of spending money on replacing the crankshaft & rods, spend your money on nitrous oxide, or perhaps later even a supercharger like what you are thinking. If you try to stroke the 305, you'll have to noodle with clearance grinding the engine block in a minimum of eight, possibly sixteen places, then dealing with crankshaft to cam clearance issues.

Have the existing reciprocating assembly balanced, add a $160 set of +.030 forged pistons (if necessary) then put your time and energy into working over the cylinder heads for air flow & performance. You can turn it into a low budget high-13 second performer that buzzes into the high 12's on the laughing gas if you do it right.

WS Sick

Too bad youre not close by here, I have 2 roller blocks in my shed that I would let go for 100$ a peice. (both still standard bore) I also have another that is just as good, but had a head bolt broken off so that would need to be removed.

92RS305#2

so your saying i should stay away from stroking the 305 and just bore it a little, a custom supercharger for my TBI would be kinda cool and when i were to get a new bigger engine i could prolly easily make it fit on a carb. i kinda also want to prove that a 305 can be a semi-performance motor, but i'm looking more at low end torque than high end HP. i'm looking at exhaust systems right now to find the one that'll fit my needs best

five7kid

Sorry to take so long to get back to you about the 305 stroking question.

The kit will cost you $200 more than a similar 383 kit. If you can't find a builder 350 block for less than $200, you aren't trying hard enough. For the extra $200, you're still going to be 21 cubic inches behind a simple rebuilt 350, for which rebuild parts are really inexpensive, and the aforementioned valve shrouding by the cylinder bore is going to hamper breathing. Even though the 334 might have a little more low-end torque than a 350, it is going to come up short on power assuming everything else is equal - every time - why spend all that money on something that is going to make less power? Just so you can be different?

I wasn't assuming any cost for the 334 machining when I said it was a poor HP/$ investment. If machining is free for 334, 355, or 383, the 334 becomes even a worse value.

I looked into all this over 3 years ago. I've kept track of price trends. It hasn't gotten any better. The 334 is a very poor choice.

five7kid

Still a poor choice. If you have to spend any money on the 305 shortblock (bearings, rings, pistons, etc.), forget it. Go find a builder 350 block.

Rebuilt 350 vs. 383 can be argued by the HP/$'s standard. No money spent on a 305 shortblock even comes close.

Unless your true goal really is limited to being "different".

85_305

Well I as well want my 305 to stand out.. as all my friends seem to think that anything will stomp on it. ( Never had it on the road yet, so no way to prove it )
But I still dont see why the major-torque increase that would be yielded from stroking a 305 isn't worth it (taking the valve-problem into consideration)

five7kid

Torque is "work" - force (pounds) times distance (feet).

Moving your car over a distance requires work - force (pounds, not the weight of the car but the force required to move it) times distance (feet).

"Power" is work over time - or, work divided by time (power = work/time). Getting from one place to another requires work; how long it takes you to do a given amount of work is called power. The less time you want to take to cover a given distance, the more power is required (time = work/power - or, put another way, to make "time" smaller, you have to make "power" bigger if work stays the same).

A 350 will have more power than a 334.

And cost a lot less money to build.

It really is based on basic math principles. I hope that helps clarify it some.

92RS305#2

i understand math, but say i don't stroke it and i don't buy a new engine. boring it for free doesn't cost me anything and if i go roller rocker and cam could i use those if i got a new 350 block down the road? if i got a new intake and port and polished it then could i use that on a new 350 block also?

five7kid

Okay, you can bore the block for free - where are your free pistons coming from?

Go ahead and do everything else, just do it to the unmodified 305 shortblock. If you need to do the block boring in school now, go get a builder 350 block, bore it out, and set it aside until you can finish it properly.

92RS305#2

i get what your saying, but will i be able to transfer those parts from my 305 to my 350 if i don't abuse the 305?

five7kid

The things that bolt onto the block, yes.

The things like the pistons that go into the block, no.

92RS305#2

okay thankx

WS Sick

Just put any SBC in there that you want and tell them its a 305...lol