Looking for some suggestions on this build, nothing crazy but close to 300whp would be my end goal. I'd like the engine to have a power and around 1000-5500. What cam/head would be good for this? What would be the cheapest route? This is the first engine build I'm going to take on so it's more for learning than anything. Well, okay the car being faster is some of it

 

Put a "bore kit" in it.

 

Do you realize what year it is?

Ever notice all the millions of 300hp 305s you see running around all over town? I mean you can hardly turn around without bumping into a 300hp 305. It's so easy to do, it's like falling off a log. I mean you just bolt on a Edelbrock Power Package and it's like 320hp.

No seriously, the vast majority of 305s are turds. Modified 305s are like modified 350s only less impressive. And everyone has at least a 350.

Please stop with the 300+hp low output 305 threads. Please. It's not going to happen. It's a waste of time. I feel dumber even seeing these threads.

 

A lot of 350's are turds to. It is 100% going to happen and not a waste of time. I should've held back on posting this thread because I figured out what direction I'm going an hour later.

 

You have your HP goal set too high-300 RWHP is about 325-340 FWHP,more than 1 HP per cube from a grocery-getter 305 Don.t be fooled by "gross"HP rated "350 HP" 327s and the like from the '60s...IF you reduce your HP goal to ~210-220 HP,things start to get decently easy and cheap and still a dramatic increase in performance over stock 170.Exhaust and cam are main hindrance with an L03,stock #187 swirl port heads are better than the bad reputation they seem to have and will be ok for mild street use.If I was to do a mild bolt-on hop- up to an L03,i would :
-decent exhaust system,possibly with small headers.
-upgrade cam with something similar to L98
-clean intake valves if coked up,mild port job if heads have to come off for the cleaning.
-upgrade fuel pump if needed.
-modify regulator and boost fuel pressure a bit
-optimize ignition timing.

 

Imagine... What if the Coyote had a helpful, friendly online forum of other cartoon Coyotes. Where he could start a thread asking for advice about which ACME product he should order to catch that damn Road Runner. Maybe the Coyote would have gotten advice from other Coyotes that have already tried the Rocket Sled, or the Giant Sling Shot, and already crawled out of a smoking crater, or gone off a cliff, or been pancaked by a falling boulder. Maybe the other Coyotes might even tell him that Slow Roasted Road Runner tastes like feces and to focus his attention elsewhere.

Sorry Wile E, that Powerhouse 334 stroker kit, and those special heads advertised to not kill your 305's compression while giving you tire smokin' torque and pavement blistering horse power, are leading you down a dark path.

We're here to help you.

 

Can't say it any better than that. have fun hotrodding your small block.

 

Well, let us know how that turns out, whatever it is.

Speaking strictly as someone who has been in this hobby long enough that I grew up building 283s and 327s and then got a glimpse when I got tired of getting my butt kicked by these "newfangled" 350 things in the mid 70s, ... LET ALONE 400s (really, the only classic SBC I'll bother building for myself anymore), allow me to give you a glimpse into the NUMBERS of how this stuff works.

HP = Torque x RPM x a constant (the constant is 2 x pi ÷ 33,000 which works out to about 1÷ 5252.11)

And, Torque = Piston area x stroke x a parameter (a "variable constant") that's a property of your engine; commonly referred to as "brake mean effective pressure", best thought of as, thermal efficiency. Which is to say, the engine's ability to generate pressure in the cyl as a result of the heat of combustion.

And, RWHP = Crank HP x .75 - .80, depending on how well you manage to get your drivetrain set up.

That quite simply means, if you want high HP #s, you have to do 1 (or both) of 2 things, since you can't change the constants.

Gotta either increase torque, or, make the motor produce its peak torque at a higher RPM, to get THAT term in the equation larger.

On pump gas, in the real world (the one YOU live in), it's REAL hard to get more than about 1.25 ft-lbs of torque per cubic inch. So out of a 305, your ideal peak torque will be about 380 - 385 ft-lbs at the crank.

To get 300 RWHP, you need somewhere in the 375 - 400 crank HP ballpark, at whatever RPM the engine can deliver that much HP.

Keeping in mind the RPM <-> torque equation, that means that your 385ish peak torque MUST occur at around 5300 to 5500 RPM.

Do you have ANY FORKING IDEA how hard that is to do, while retaining ANY SEMBLANCE of "street" (daily driver) characteristics??? You will end up with NO BOTTOM END WHATSOEVER; that is to say, your existing 2.73 or 3.08 gear with the stock converter (or clutch) won't allow your engine to make power that exceeds WHAT YOU HAVE NOW until you reach somewhere around 60 mph IN FIRST GEAR. Your gas mileage at RPMs below 3000 or so will likely be better expressed in GALLONS PER MILE than miles per gallon. Which means, if you build such a motor and plop into your otherwise unmodified car, it will be slower AT ALL TIMES below that speed, and will ONLY begin to exceed your current stock behavior IF YOU HOLD IT IN FIRST GEAR TO AT LEAST 60 MPH; and all the rest of the time, it will be SLOWER and at all times VERY EXPENSIVE to operate. Is that consistent with the circumstances you drive within? Might be OK for a strip-only car, but most of the people I've ever built motors for over the years (probably not more than 100 or so) who were "first timers", aren't strip-only kind of people.

And that "expense" doesn't even begin to take into account the cost of parts breakage... and I can assure you, this hobby becomes ALOT less fun IN A HURRY, when you have to keep buying stuff because you're constantly operating everything at the edge of survivability. Again, not a good intro to the hobby for a first-timer.

Put a "bore kit" in your 305. Makes it AHELLUVALOT eeeeeeeezier to do what you say you want to do. Especially for a first-timer.

With a 4" bore, your peak torque RPM instantly becomes about 17% lower, for the same goal. Cubic inches are your friend.

 

I have a Vortec 305 in a 1999 Tahoe that did 260 rwhp @ 5,200 rpm and about 280 rwtq @ 3,800 when it was dyno'd. At 18% loss that is about 320 hp and 340 tq at the crank. The cam is fairly aggressive for a 305 especially with a Vortec intake manifold and would likely make about 20 hp or so more with any other intake. Vortec truck intake is absolutely horrible in design but works ok in this application. The Vortec intake is so bad I have considered swapping to a TPI Vortec base and a stock runner TPI system. TPI would add 20-30 ft/lbs of torque through the midrange and give me another 20 hp or so and flatten the HP curve from 5,000-redline by not dropping off as quickly from lack of breathing.

Its just a high mileage 305 Vortec that was honed, flat top 1.56" compression height pistons, polished crank, new bearings, 218/218 @ .050 flat tappet cam, 1.6:1 full roller rockers, Volant CAI, long tube 1 5/8" primary headers, 2.5" dual exhaust to the muffler, a magnaflow muffler, and some PCM tuning. With a few changes like electric fans, underdrive pulleys, exhaust cutouts, and intake porting I feel I could get it into the 270-280 rwhp range but to go further would mean more cam than the intake/stall/gearing could work with in the heavy Tahoe.

 

Forced Induction. Nothing wakes up a motor like a blower. Of course, that isn't really 'budget build' material......