I want more revs outta my 305, but I wanna keep it 5.0-ish. Would it be possible to bore it out .30 over and put a 289 crank in it? I know it will loose torque from stroke, but I can just put a 3.83 or higher rear end to build torque, and I'll get the torque through the entire range, which would be longer. What RPM can I expect with headers, RV cam, and LT1-style intake? Would it be possible to make 400-450hp with the right tuning?
Thanx

 

no to everything you ask

 

a 289 is a ford....

 

RV cams are crap, 289 is a ford, no such thing as 3.83's for a 7.5 inch rearend and not in your wildest dreams would ya get 450 HP from a N/A RV cammed 305, probably more like 250 at MOST.

 

as in Recreation Vehicle? your joking right?

 

That is a wild imagination.

 

never figured u for a gearhead homer, what are those lt1 intakes? yup. ford crankshaft? yup. RV camshaft? nothin but.

i made the last one up homer.

i ssseeeeeee

:lala: :lala: :lala:

 

Ok, I meant 283 crank. They put LT1 intakes on 350s, I'm sure the same swap will work on a 305. And, by RV cam, I don't mean go take apart a Winabago, I'm talking about a camshaft thats only a couple steps over stock, build power, without losing low end or vaccum like with a bigger cam.
So, could someone explain to me why this wouldnt work, becuase, as far as I know, it should, and there are 302s out there making good power?
Also, I thought my car had a 10 in. rear, not a 7.5?
Could someone answer me thats not gonna be an ***, please...

 

What is typically referred to as a "RV cam" is the opposite of a "performance" cam. It is designed specifically to produce lots of power at low RPMs, at the expense of higher-RPM power. It is not the answer if you want to go fast. If you want to enhance a motor's high-RPM breathing, you do the exact opposite; you use a "bigger" cam, which optimizes high-RPM performance at the expense of low end and vacuum and driveability and gas mileage.

You don't get more power by down-sizing the motor. Period. This fantasy about de-stroking motors comes up pretty often, and usually leads to a big argument and flame war; mostly those of us who have been around for a while and experienced the old small-inch short-stroke motors and who know what they are like, againt a bunch of inexperienced people that somehow get this notion that shortening the stroke a little bit produces this massive rev capability.

The reality is, the stroke has relatively little effect on the engine's output vs. RPM curve. The difference between a 327 and a 350 torque peak, for otherwise identically built motors, is only about 200-300 RPM. Problem is, to raise the peak torque RPM by 300 that way, you cut the absolute value of the motor's torque (output) by 7%. That's about 21 HP you lop off of a 300 HP 350.

The effect on a 305 would be similar, since it has the same stroke as a 350. If you could put a 3" stroke crank into a 305 block, you'd cut the power output by about 15%, in exchange for about a 500 RPM higher torque peak.... that's 15% less torque.

An engine's rev capability comes from flow, which in turn comes from head characteristics and valve action. Go to a World Of Outlaws race sometime, and see if you can guess the Rs that those guys run at down the straights. I'll guarantee you, there's no 3" stroke cranks winning those races; and the reason is, the more you pack in there, the more power you get out.

It's all numbers. You don't get more out of less. That short stroke high rev crap is pure fantasy land, and the road to an expensive disappointment.

If you have a 3rd gen, you have either a 10-bolt rear with a 7½" ring gear, or a 9-bolt with a 7¾" ring gear.

 

Thank you. Thats what I needed.

So, is it possible to get high revs and 350-400rwhp out of a 305 with head work, larger bore, BIGGER cam, higher compression, and no stroke reduction, and redo of everthing else? or am I gonna have to do a 350 swap?

 

For the money you would spend in boring, etc. you may as well do a 350. Blocks are cheap. To get 350-400 RWHP, that would be a very radical 305, too much for regular street use. Do a 350 if you want that kind of power, you're spending money anyway.

 

there is no replacement for displacement, oh wait, yes there is, FORCED INDUCTION!!!!! but that wouldn't be cost effective either for someone wanting to run this thing on the street everyday. there are some people on this board getting very impressive numbers out of there little 305's which can be very reliable motors. however, to make the wierd bore/stroke combination make serious hp, it takes alot of time and money. do you have either? i am considering a 305 buildup of my own. only cause i have one sitting in the corner of my garage and the possibility of my 350 block being trash is definetly eminent. however, a naturally asspirated 305 will not hang with it's bigger brother 350. so naturally, it will be blown, a little 144 powercharger sitting on top sounds good to me. but the 305 is a back-up plan as the pistons alone will cost $60 more then the 350. so, as you can see, a 305 will not produce as much power as a 350, and a 350 will cost less. you do the math.

 

Around 300-325 would be about the limit for a 305 IMO. That is what I am expecting once I finish my 305. Of course, you could add a blower on it or some NOS but in the case of NOS, if it's not there all the time then why have it at all. NOS is useless to me. The blower on the other hand would be nice.

 

The SCCA A sedan racers are getting 385-400 hp at the flywheel and that's with stock unported heads and .480" lift cams. they run Edelbrock performer RPMs with 600 cfm holleys and are limited to 10.3:1 CR.. These are too much motor for regular street use. Any NA 305 making over 350 hp is probably going to run pretty radically.

 

There's not way you're going to see 350-400rwhp with a 305, that would mean you're pushing 413-472hp at the crank, which is very difficult (impossible for a street motor N/A) for a 305. Here's what I would reccomend to reach your goals:

350 block
Vortec heads
XE274 cam
Performer RPM intake
10:1 compression
Holley 750 carb

That setup will produce 420hp at the crank which translates to about 344 at the wheels (assuming 18% loss) which is enough to run 12's at the track on a fairly low budget.

 

if you're looking to build something that rev's out of a 305 based block use a crank from an L99 in an 86 or later block with the 5.94 rods from the L99 and either 10:1 or higher compression with nitrous or 9.5:1 and lower with a 144 blower and as much boost as possible. use a real cam, not an "rv" cam. the term "rv cam" has as much real terminology to it as a 3/4 cam.... bore it .040 to .060 over with a head like fast burn's or trick flow's. that should get you started.

 

If you want to keep a 5.0L engine, get a 350 block and a 3" stroke crank... 302ci which is 16cc's short of 5L

A properly built 302, you can rev the snot out of it and it will ask for more, mainly because it has the same size valves as a 350, but has alot less cylinder to fill, making it easier to make an obscene amount of high rpm horespower.

I'd just go with a 350 though... ci's are your friend