So my buddy just did an engine swap in his '84 Camaro, and has his old 305 just sitting on an engine stand waiting to be torn apart and rebuilt to be a beastly little 305 that would go nicely inside my RS. As I was helping move some drywall he offered to let me have the engine, for free. It's no 350, but a free 305 definitely has some potential to put out some decent horsepower on my 92. I will however have to have my differential and gear ratio changed because I'm running an open dif with a stupid 2.73 pinion. So, this new engine after it's all built up probably wont like the RPM that my dif runs at. Stupid 2.73. Feel free to make suggestions on a dif that will fit in a 7.5 x 7.65 10 bolt housing.

Anyway this is where you guys come in. I need some help picking out good parts that compliment each other to make this 305 live up to its potential! I know I would like AFR heads, and a good Comp cam with a max lobe SA of 112 and minimum in/ex lift of 450/460 (preferably roller). Duration I will let guys decide hat is best. I don't know if I should run 1.5 or 1.6 RAR. I'm unsure of what intake manifold and carburetor combo I should go with, but I have heard that an Edelbrock intake and Holley carb combo goes well. No clue what my CFM should be. So guys, help me out! This is my first engine build and I am just excited to start learning! This engine is an 87+ SBC. I will get a cast number for you guys soon enough.

I would really like to try and get 400hp out of this thing, though that may be a little far fetched, but with the right parts and tuning,I feel like it might be achievable. Lets do this thing!

 

I have a 600 cfm summit carb on my 358 in my 92 Camaro. I find that it does well.

 

If it were me I would just do a cam swap in the motor and leave the bottom end and heads alone. If it is a roller compatible motor doing a roller cam swap might be worth it though as you could later easily swap this stuff over to a 350 and re use it. For cams I would recommend something like the XR264HR from comp cams. This would probably only be good for around 275 HP at most in your 305 but in a good 350 with good heads could be good for around 325-350 HP later. For intakes I would recommend a Performer EPS from Edelbrock with a 600 CFM vacuum sec carb. If your still looking for more power I would recommend a nitrous kit with a 100 HP shot. It would take a lot of money to get an honest 400 HP from a 305 as you would need very good heads to get there or dissent heads and a lot of RPM.

 

Chevy High Performance did a build where they got 345hp from a 305. So 400 and drivable with a carb is going to be $$$$$ 300hp is much more reasonable and doable on a 305.

1.I would get a retro roller rocker set of lifters. Then a roller cam. Something like this: Lunati 20080720. A next step up would be the 20080721 that I have in my 355.
2. Trickflow 58CC heads or World S/R Torquer 305 Heads. The 64CC heads normally found on a 350 will kill your compression. Either way, you'll want some port work and back-cut valves.
3. Flat Top 9.5:1 or 10:1 compression pistons.
4. To get closer to your target HP number, You'll want to stroke it. Look up the specs on a 334 CI motor.
5. Your intake will be an edelbrock performer and any 600cfm carb or a vacuum run Qjet (best option IMO). You can run an Edelbrock RPM performer but you'll need a drop base air cleaner.

This will get you north of 300hp but it won't be cheap.


Now my only question is, why do you want to go Carb and get rid of your TBI? A properly built TBi can easily hit 300-350hp. Totally your car so do what you want, I'm just curious because I'm actually looking to go from carb to Fuel Injection. Kind of the opposite of what you're doing.

 

I don't like working with the ECM. I prefer straight up mechanical.

 

Before you take this the wrong way - most of us had 305's at some point. Been there, done that. I understand where you're coming from, but let's put things into perspective.. There's a million of these 305 threads, and it's because most of the users here are either dreamers or cheapasses. Not saying you're either of those, but realistically speaking - a 400 HP 305 SBC isn't going to be as pleasant of an every day driver unless you really have some custom tailored parts for the motor. That's big bucks AND settling for less.

Look at it this way: You're willing to spend several thousand dollars on a motor I can find all day for $200 running and driving.... Because it's free? I can lay a turd in my hand and give it to you for free, but that doesn't mean it's a great idea for you to take it from me; even moreso to go off plating it in gold..... Want cheap 400 HP? Go buy a 5.3 LS motor for $350 and drop a cam in it. 6.0's can be had on average for about $800-1300 or so with decent miles if you want easier HP in the 5-600 mark.

 

LS motor does sound nice, lol. But I find it hard to believe I can get one for $350, especially in Nebraska. You're definitely right on all accounts too, I would rather have a 350, and I want one so damn bad. But as a first build, idk if its really ideal. Or is it?

 

Man,

You can find any old 350 block in any old junk yard for under $200. $350 for a complete rotating assembly. I'd get one 96+ simply because it's a roller block. Then $350-$400 for block prep work, L98heads. or Vortec's would be better, also from a junk yard (or from a member here in good shape fairly cheap) and you can be on the road for $1500 or so.

That said, this is your first build. Take whatever you budget, then add $2000 and you'll be in the neighborhood of what you'll spend unless you have some good quality assistance.

 

I see them for $350-500 here all day long with lower miles. High(er) mileage 6.0L start at around $750.

an LS would be cheaper power-wise, and for drivability reasons. Your most expensive investment for an LS motor is the headers, realistically. Don't get me wrong - I LOVE SBC motors and always will... but I've seen those 5.3's so cheap, and they run great.. sound great. Great stock cylinder heads for "cam only" setups. Already hydraulic roller. We're talking a potential 11 second car on the cheap. Next generation and iteration of the SBC engine (after the LT1, of course). Swap parts and write-ups/videos are everywhere now as opposed to 10 years ago, even..

What's not to love?