13.4 @ 100.7 mph thats the best i have ever done, the tires griped like never before i usually run 13.5 or 13.6

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90 RS 305 tbi, 4 3/4" cowl Hood, Edelbrock TES headers, Flowmaster exhaust, Crane roller cam, comp roller rockers, vortec heads/intake, ported tbi, w/new injectors, MSD probillet Distributer/ coil, 1 inch tbi spacer, air foil, 14x4 k&n flat base air cleaner, Rebuilt 700r4 w/ B&M shift kit, B&M Megashifter, 3.23 posi, 2 12 RF's with mtx amp, top of line alpine cd player, soon to have 90-91 gfx, z-28 wing, new paintjob, rims, and all new lowered suspension.

 

hey I like this thread. I want to build up my 305 to go as fast as possible for very cheap.
Give me some more ideas please.



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1986 Iroc 305 small block chevy getting modded now for speed

 

You build the 305 just like any other sbc. It isn't that the intial cost in parts is cheaper for a 305 compared to a 350...just the fact that you already have the block and it is in your car makes it cheaper, that is if you plan on keeping it.

Email if you like to know what I"ve done.

 

Just because a 383 is a longer stroke than a 350 doesn't put it in the same category as the 305. The absolute size of the bore, not the bore/stroke ratio, is what makes the 305 weak. The 305 bore shrouds the valves, the 350/383 bore does not.

 

Yes, I can tell you know what I'm saying here, and it's nice that your on the same page.
400 = 1.100
383 = 1.074
350 = 1.149
335 = 0.9973
327 = 1.2307
305 = 1.074
302 = 1.3333

Again, notice the bore/stroke ratio on the 383 vs the 305...

 

Notice that 302, too

No wonder they rev so wildly!

 

Hawk and Mello,

You guy's are missing my point. The Mustang 4.6 has a much smaller bore than the 305, and w/2 valves/ cylinder, it should only be able to make about...NO POWER, right?

Let me elaborate here. The accepted theory is that a 305 doesn't make good power because the valves are shrouded by a "small" cylinder. At 3.74" the bore isn't THAT small, compared to MOST engines on the road. But that is beside the point. The point is that if you could take a 305 and expand the bore, and shorten the stroke, (like if it were made of clay, lol) then you could fit larger valves and get more flow and power. At that point you would essentially have a 302. So according to popular opinion, stretched and shortend motor would make more power

So now let's take a 383. Wouldn't it too benefit from a larger bore? (Which would mean shortening the stroke to maintain the displacement) Yea, the 383 has a bigger bore, and bigger valves, but with the longer stroke (than a 305) the 383's cylinder is going to be trying to draw more volume of air, thus turning the valve/cylinder bore relationship into the same relative restriction that the 305 "sees".

Another point: A 383 w/a 2.02 valve has a bore/valve ratio of 1.980. The Cylinder is 1.98 times larger than the valve.

A 305 w/a 1.94 vlave has a bore/valve ratio of 1.93. The bore is 1.93 times larger than the valve. That is a pretty close ratio.

The more I think about this issue, the more I think a 383 is just a big, dumb, 305. LOL. I really think that with these ratios I just mentioned, the 383 ought to have the same technical handicap as a 305. Don't MOST 383's rev to about 5500 - 6000 RPM and not much higher....and don't most "stoutish" 305's? The 383 just "seems" to work better by virtue of it's shear size. No?

 

Truth be told, I didn't even read your post before posting myself, but it doesn't matter. Although your comments on bore/stroke ratios are intersting, they don't offer much to the hp per $ equation.
Maybe my Briggs&Stratton has the same bore/stroke ratio as the 305 and the 383 - you wont see me use it in my car though, because in this case of hp per $, BIGGER IS BETTER.

One way to make up for the use of so-called small valves is to have your heads ported, which is very expensive. I would pay for an out of the box, unmachined 383 before I would pay for a fully ported, custom machined 305 any day....like i said earlier, hp per $ here.

And a 6000 rpm 383 lazy? I would rather have that on the street than the 305 you would have to rev to 7000 to make the same power any day as well.

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1990 Firebird Formula 350 speed density TPI; Edelbrock HI-FLO base and Runners w/portmached plenum; air foil; Comp Cams 1.6rr; Edelbrock 1&5/8" headers; MSD 6AL, HEI coil & plug wires; underdrive pullies; Hypertech stage II chip; AFPR; B&M stage II shift kit; 3.73:1 rear; Jamex 1.5" lowering coils; Spohn subframe connectors, LCA's, and LCA relocation brackets; free mods; !cats; !Smog Pump; PLUS...1300w stereo weighing 200 lbs.

[This message has been edited by MelloYello (edited November 06, 2001).]

 

Ok im not the smartest guy here but some of you guys are thinking about this all wrong. Think of it more Like stroke=torque bore=HP Now with that said the 350 is better than the 305 for two reasons the bore is bigger and the valves are not shrouded. Now when you go to a 383 the valves are not shrouded and it is a he** of alot bigger than a 305. The way I figure it the 383 is better and worse than the 355. Basicly you are trading high end HP for low end torque. I now own a 383 that i swaped from a 355 and my times didnt change much but it is more fun to play with on the street. Personaly I say If you can put the power to the ground go with the 383.

That is just my .02$

 

Don't buy a 305 car in the first place if you want performance. You buy a 305 car because it is cheaper. If you want an engine that makes 550 hp and will last the 454 is probably the best value.

 

How the hell did this post come back from the dead?!?!

 

You took the words (almost) right out of my mouth.

Since this all transpired before I did my mods last November, I'll just add this:

I'm still looking for the guy who spent $1800-2000 putting a 350 in his car (about what I spent on my 305 mods), still running through the LG4 exhaust, that is willing to run me in a match race.

Any takers?

 

You Can purchase a 383 from Mopac in Canada for under 2200 AMERICAN when they're on sale.
350 hp 400ft lbs

 

Okay......

Put that $2200 383 in, with your stock LG4 exhaust manifolds and exhaust, and I'll still run ya...

 

Ok lets put this to rest 305 good 350 better. Now if you only want to make it up to 300 to 350hp and you have a 305 i t just might be cheaper to use your old 305 but if you wanna shoot for 400-450 its going to be cheaper to use 350-383 Period. Now my brother has a tbi 305 i think he should stick with it and mod it a little because 300 hp is no joke and it will be cheaper for him to get it out of his 305. a little spray and exhaust and he should be over that. $400 for spray and $700 for exhaust and headers. there thats 300+hp for just over a grand. now if you want to go over 400 your going to be tearing your block down and replacing internals anyway so please just go 350 its easier.

There it is just that simple.
I know that 305's are no joke there are a few of them running 10's. so dont ever ever ever knock a 305 because he just might spank you. but dont get to cocky either 305 guys.