building a 305 h.o
 

do yoyu think building a 305 h.0 is a good thing or bad?if yes why? if no why?

thanks dman

It's a good thing if you have a 305 HO that doesn't need any bottom-end work. As a former 305 H.O. owner, I did the buildup, and managed to peak out at 262 RWHP, and hit some 101 MPH flat-14 second quarter mile time slips for about $800 in parts.

It's my opinion that as soon as you need to pop pistons out of the bore for a rebore, it's time to remove the whole engine and replace it with a 350 if you want ultimate performance. Otherwise, it's a good economical alternative.

In other words: If you can get by with a simple set of gaskets, bearings, re-ring and bore hone, go for it.

I've got more information on the 305 HO buildup here:
http://www.ws6transam.org/fcar.html

I also cover how to port some good 305 heads for airflow that will yield you 300+ HP with a streetable cam.

A guy on thirdgen.org ran a mid 12 second in the 1/4 with a 305....ALL MOTOR....


If you have the time and money I say go for the gold man, you can easily do what he did, and then put a power adder on there if you wanted to and you'd see 11 sec. slips all day long :)

That was Matt, but it's not that easy, seriously don't sit here and try to have another member believe this, he spent thousands on that car, even though the motor was only mildly built.

He did substantial weight reduction, I mean crazy: Fiberglass hood, removed ANYTHING that he didn't need: GFX, dash components, the spoiler, aluminum brakes, aluminum driveshaft, power steering, emissions, sound deadening material found under the carpet, etc. This was key. I believe he got the curb weight under 3000lbs.

Then he fully modded his suspension, and ran huge slicks in the rear. He also had a rear that could handle all the hard launch abuse with 3.73s. Also, he put in, what I believe was a 4k stall.

Matts 305 didn't make his car fast, his CAR made his car fast, big difference here.

That is one of my favorite motors in the IROCS. Its powerful and simple. It's the L69 right? Build it. No cons. Only Pro's. 190HP stock and a 5-speed. Keep us posted on this. I would think your motor could be modded and be fast on a budget. Good luck.

I say build that 305HO and show the world whats up with 305's. Cam, intake man., headers, customs mandrel exhaust (3"), hi-flow or even a Cat. delete, better upper plenum (don't know much about EFI.. maybe a Holley Stealth Ram or a Mini Ram??), underdrive pulley's, emissions delete, and a shift kit if auto and you will be haulin' balls in no time. Trust me.

Would need to redo the entire intake (and prolly the computer) if he was to make a carbed car EFI...... :shrug:

Not a bad idea, but prolly more costly then finding an EFI motor to drop in it IMHO.

I hope this isn't going to turn into another "I ran 9's with my stock 305," thread!
There are only a few good reasons for modding a 305, depending of course on how much hp your looking for. But in any case you can achieve the same or more hp with a 350 or 383, for the SAME or LESS cost. The reason I say this, is because the cost of components for SBC's is appoximately the same. I.e., if you buy heads at level X for a 305 they will cost the same as heads at level X for a 350. A forged crank that can handle 7000rpm for your 305 will cost the same as a forged crank for a 383, that will handle 7000rpm.
As an example, if you go to AFR's web. site, you'll notice that all SBC heads are all listed together. They don't separate them into 305ci, heads and 350ci., heads, etc. So the 210cc race heads are the same cost wether you put them on a 305 or a 350.
The problem of getting power out of a 305 should be obvious, in order to get high hp levels out of a small engine you have to either rev. it higher or put a power adder on it.
Again the money you spend on a power adder, be it blower, turbo, or NOX, will be approximately the same for any ci engine, and will still require expensive internal mods. to support them.
Now if your building an engine for a spec. class, that restricts engine size, of course that's different.
I haven't checked, but I would be willing to make a virtual bet, that if you have two guys with 3rd Gen's, both 305's and both needing rebuilds. And you gave them each $3,000.00 dollars. And one rebuilds the 305 and the other buys a 383 off E-Bay, the guy with the 383 will have more hp.

Theres no replacement for displacement :cool:

But just like you said, why waste money on a 305, when a motor that is 45 cubes bigger would cost the exact same amount? This has always been my thinking. Dont get me wrong, 305s can motor, Ive seen it, but to get the most out of it, you are going to want a 350 at least.

And some of you guys are going "prove it, show them what 305's are made of!", theres nothing here to prove, we already know that 305s are a capable motor, but 350s are just 45ci more capable. Honestly, if you had $4000 to throw at a motor, would you really sit there and say "yeah I'm gonna build a 305 because I have something to prove"...no! unless you have that kind of money to throw around, but really this is not the case. Don't sit here and tell someone to throw hard earned money in to a motor that plain just wouldn't keep up with a 350 dollar for dollar, just so you can see a video on youtube months and $5000 from now of this guy pulling a bolt on LT1, when he could really be pulling a heavy modded LT1 or an LS1.




Bottomline, do what you want, but the fact stands, dollar for dollar, 350 beats 305.

Lol what would that be, like a 320?

327 I believe.

I have seen 305 stroker kits on the internet for $600, I've seriously considered it. ;)

The thing the OP has to consider is does he want to keep the original 305 or can he afford to upgrade the short block to a 350/383/etc? That isn't free and he apparently already has the 305.........if he isn't looking to be the fastest car on the block but still have some respectable power and more importantly, a fun car to drive, he could build up a 305 to a decent power level without the cost of obtaining a new block. :dunno:

On the other hand, if the 305 is tired, worn out, high mileage, etc, he may be better off with a crate 350/383 and go from there........might cost close enough to properly rebuild that 305 as it would to get a bigger SBC.

yeah i'm pretty sure its the same size pistons as the 305 w/ a longer throw on the crank that gets it to 327.

I love the old 327, my buddy's dad has a '63 Impy w/ a 327 in it. You could rev that thing forever and it would just go with it and ask for more..... of course it had the 2 speed powerdrive tranny in it so you weren't shifting many times anyways

Sorry folks, but the 305 stroker kit doesn't turn it into a 327. A 327 is a FOUR inch bore with a 3.25 inch stroke. A 305 is a 3.736 inch bore on a 3.48 inch stroke. A full quarter-inch difference in cylinder bore. I wont discuss it any more than that in this thread, but 305 + stroker crank does NOT equal a 327.
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Again I say:

"Top-end only" build-up of a 305 H.O. = Good thing.
Full longblock recondition of a 305 H.O. = bad thing.

When it requires you to pop pistons out of the block, it becomes more economical to replace it with a 350.
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