I have a 50' F1 that the previous owner put a 305 and 700R in. The 305 has headers, edelbrock intake and carb.  I have seen posts that say you can modify these and others that say dont bother get a 350. I have to pull it anyway and was wondering everbody's 2 cents?

John  

Any smallblock Chevy will respond to modification, even the lowly Monza 262 made for a limited time.  But dollar-for-dollar, you'll get more bang for the buck with a 350 than a 305 because it has more cubic inches.  One of the guys at work built a 305 with 330 RWHP off the bottle. Had it been a 350 it likely would've been a lot more.  But don't discard it just because it's a 305; any Chevy smallblock will respond to a well-scienced modification scheme.  The 305 suffered from thin walls and cracking heads/bad valve guides when it was introduced, but Chevy fixed all that soon enough.  

When I blew the 305 in my Iroc, I wanted to put a 350 in it's place but there were issue's and i just rebuilt the 305.
I started with a Crane Compucam for a little better power range went with a .423 cam(now upgraded to a .460/.460 Comp Cam). I then added a ported and polished heads, headers(of course)an air foil from Hypertech. She responded well. Went from a 16.1(4200ft above sea)to a 14.8 a few months after break in. Now I have added a rebuilt 700R4 with a Trans Go shift Kit and a Big End Performance 2400 stall tq converter with the new Comp cam and hoping for more. I am currently switching from the V-belt setup to a serp setup so no times as of yet.
Yeah I would be faster if I had thrown in a L98(350 TPI)but I didn't and I am happy with the results so far. It's kinda dissapointing that my stock Trans Am LS1 ran a 13.8(same track as Roc 4200ft)(best of 13.1 at 600 at SAR) this past march with a new lid and Flowtec cutout vs my 14.8's in my Roc but it's ok. I am hoping to be at around a 14.1-14.0 with the new setup before switching from 2.73's to 3.42's. I have since moved to Phoenix so now we are at 1200ft vs 4200 so it's hard to convert but I should be at a 13.1-13.4 area I hope.
305 is good but more cubes is better. I wouldn't take it back though, I'm happy with my little 305  

You know what they say, theirs no replacement for displacement.  

I've heard that the 305's can't quite handle big time upgrades, something about cracking blocks  

I am building a 305 for a daily use, This will be my first engine and I want to prove my self I can start building bigger engine. If I blow an engine I rather do it with a small engine like 305, cheaper.... but again 305 are not as strong as a 350 or 402 big block...  

<strong>If the 305 is what you have, and you are happy with it so far, then modifying it instead of going out and adding the extra expense of another whole engine makes alot of sense. It will respond to mods like any other motor, but a 350 usually (all other things equal) respond better.</strong>  

The 305 has two strikes against it: less displacement, and a smaller bore diameter.

While most people cite the smaller cubes as the primary hp killer, it is actually the small bore (almost a quarter inch less than a 350) that restricts hp potential the most.

The engine's hp is mostly a function of the air and fuel you can move into it. A small displacement doesn't preclude that, but a small intake valve with a shrouded bore does.

I would not pick a 305 as the basis of a performance build, but next to the 350, it's probably the most prolific V8 ever built. If it's all you can afford, then go for it.  

<strong>The small does have one advantage though, it has been found that smaller bores have less of a tendancy to detonate, due to the fact that there is less room for gasses away from the center of the combustion chamber. The effect has not been found to be a huge difference, but if your riding the edge with your engine, it may make a difference.</strong>  

83 malibu wagon (3500 lbs.) 13.70 @96 mph w/305 heads never been pulled.is all in the combo!cam,intake,carb,converter,gear,sticky M/Ts.  

just my 2cents 88 monte ss stock motor 230,000 ran 8.9's 1/8 mile  14.10's 1/4 headers true duels and a turbo 350 trans nhra stocker run well into the 11's with the 305  

stroke a 305. give her a good air-gap intake.cam her with atleast .477"lift.blow away hondas all day. and get decent gas millage.  

I had a full size 1986 GMC 4x4 for my first truck and it had a 305 in it. Every time someone would ride with me in it they would say "man this thing is quick and it sounds nasty whats in it?" When I tould them it was a 305 nobody would believe me so I showed them the 5.0L on the rear of the block and made believers outa them. It had a mild cam and a stage 2 b&m shift kit and exhalled through 18" glass packs with 2 1/2 inch pipe, also it got about 18 mpg.  

I guess it ALL depends upon the desired results as to whether it is a good move or not. BIGGER engines are able to make more ultimate power IF that is the only criteria!
I have already built two for customers and now in the process of a third "stroker" 305 to replace a 350 in a towing vehicle which has factory throttle body fuel injection; (installing a 400 crank & rods in a 305).
NO ECM changes need to be made and better part throttle torque and more milage, (almost 20% when towing a trailer), is the outcome. The 334 cubic inch set-up which, because of it's small bore, will accept more compression with regular gas and uses a towing hi-torque camshaft to boot.
What parameters YOU expect from the results is the only factor.