My 305 tbi needed some freshening up, so I pulled it out and started looking around for some upgrades since I was already tearing it down. Ended up finding a 1986 305 short block that has 0 miles on a rebuild, it has flat top pistons, and a torque favoring 'towing' Cam, though I don't know the manufacturer. Anyways, I figured this would probably do much better than my old block, so I reinstalled my old heads, and picked up a cheap intake from an old El Camino as well as a q jet. It runs well, much better than the old tbi, but I was wondering what I could do for under $1000 to wake it up a little more. My idea is to get some reassembled/spec-rebuild 58cc heads from Aerohead Racing, with 2.02 valves and a 3 angle job, as well as an Edlebrock Performer intake manifold. I also have a guy willing to trade my q jet for his Holley 650cfm (vacc. secondary) carb. How much of an improvement do you think I'd see? And are there any other cheap 305 bolt ons that you would recommend? I already have headers back exhaust and a spectre extraflow aircleaner.

 

why 305 when you can 350 ? you'd get more bang for your buck if you went 350.

 

The 305 was built as is for $550, and I leave for college soon, meaning no garage or time to work on anything. I needed something that I could make run fast, plus it has extremely low miles on it. I want more power, but I don't have the equipment or time to pull the motor again, hence I'm just doing top end work. Eventually I want to go 350/383, but it will be a while, this is a daily driver and sees a lot of use.

 

With those exhaust done you've got a good start. I know its good practice to use things that you can put in a 350, for when you do upgrade to save money. Good vortec heads and a decent cam and tune. That's about the cheapest and best way to get power from what I've seen

 

"Towing" cam huh. Lol idk if id went with a 305. You need to find out what the specs on that cam is. Need to make sure it is matching ur compression ratio. Specially if ur gonna get new heads. Better intake, headers, and full exhaust. The exhaust with headers is good for 30- 50 hp on these cars there extreamly choked.

 

The headers and exhaust are already done, and the difference is incredible, is there a simple way to check my cam specs other than buying a cam checker tool? I'm trying to get into contact with the guy who I bought the motor from.

 

Yeah, esp. after swapping over to carb. Should have gotten a vortec 350.

 

Also, if I were to swap out the cam, whats a good cam for a 305 if I'm looking for approx. 325hp but don't want to lose any bottom end. The mystery towing cam pulls really well from idle.

 

I'd call a place like comp and tell them your expected set up and HP goals. They can give you a good list of cams for your application

 

Okay, thank you apie. Also, I know everyone will tell me to get a 350, i understand why, I wish I could, and I probably will one day, but here are a few reasons why I can't now.
1. I don't have time to build one and drop it in before I leave for school, and I can't start a build while in college as I'll have nowhere to store a block. I can do heads/intake/carb rather fast.
2. Even if I did, I don't have the equipment to do the swap now, and I surely won't on campus.
3. The 305 bottom end has about 150 mile since a rebuild, hard to find a 350 in that shape for cheap where I am.
4. I can do heads/intake/carb on the 305 for about $800, which is all I have to spend at the moment as a broke teenager, a stock running 350 with comparable miles will cost more.
5. (Not a real good reason, but a reason none the less) I have two buddies in town who have third gens with the 350 tpi. Both of them already hate that my 305 can keep up with them, they think that their 350s are unstoppable because they can beat a handful of V6 rustangs, I'd love to jump them in a 305 and watch their blood boil

 

If I can't find cam specs, then Ill probably replace the cam with this as my full setup:
Aerohead racing heads (ARO-CH-SB350SS), 58cc chambers, 1.94 X 1.50 valves (or 2.02 if it is worth it on a 305), 3 angle valve job, .525 lift springs, $400 (without port work, will it be necessary for 300hp?)
Edelbrock Performer EPS Intake Manifold (2701), $150
Holley 600cfm carb (don't know part #, square bore) $0 (trade)
Lunati hydroulic flat tappet camshaft (60102), 262/268 adv. duration, 112 lsa, .468/.489 gross valve lift, 1800-5800 rpm range $120

 

Keep in mind, that price for those heads is EACH, not for the pair.

DO NOT buy ANYTHING specific to a 305, that is to say, that you can't swap over to a 350 later. 58cc heads belong in that category. A BAD BAD BAD BAD BAD BAD idea for wasting money on.

I'd recommend that you leave the motor alone at this point and look at gears, torque converter, and suspension instead.

The way to make a car go faster is NOT to unbolt and re-bolt the big shiny things that sit up top and make all your friends ooooh and aaaaaahhh over all your square inches of chrome. Save that for the 8-yr-old kids in parking lots at cruise-ins.

Nor is it to just go out and plop down cubic giga$$$ on what "everybody" "thinks" you need. The only way that makes a car faster, is by weight reduction, concentrated on the driver's wallet.

The way to make a car go faster IS to identify THE ONE THING MOST LIMITING ITS PERFORMANCE, commonly referred to as The Bottleneck, and upgrade it appropriately in line with the rest of the combo and the goal or intended purpose; which will then expose something else as The New Bottleneck, at which time you do the same thing; and so forth.

Much of the time, if not MOST, The Bottleneck ISN'T under the hood at all. In the case of a L03 car, once you've got rid of the crappy exhaust, heads, and cam, you've done about all you're going to do in the engine compartment for SEVERAL iterations of finding and fixing The Bottleneck. That's where you are now.

Gears, converter, and suspension. In the suspension area, consider control arm relocation brackets, new springs & shocks, sway bar bushings & end links, and good tires. (as well as of course, fixing anything that's just outright "broken"; I'm talking about these things in the list as "upgrades" as opposed to "repairs")

 

Actually that is the price for an assembled pair, not an individual head. Also I have done a good amount of suspension work already (shocks, rear springs, z28 rear sway bar, new bushings, spohn sfc, and im looking for a stb that will work with my carb?) and swapped the rear end to a positraction, and have 3.42 gears ready to go in. What torque converter would be a nice upgrade but still very streetable?

 

The tires are also fairly new, and about the heads, they come in 64cc as well which could go on a 350, I just don't think I'd want them on a 305, 64cc are the same price

 

Those aero heads are priced for the pair but there is NOTHING better about them. They are factory rebuild heads.

"These heads are reconditioned and come assembled with a "like new" apperance and quality, with all new Aeromaxx parts installed and a milled deck surface"

It's not a performance head. They do have a larger intake valve but trust me you will NOT see a $400 worth of performance gain in a 1.94" vs 1.84" intake valve.

You MIGHT pickup 5-8 HP with those heads.

You can't use a 2.02" valve on a 305. The valve will hit the side of cylinder wall/block deck. 1.94" is the largest you can go and then really it becomes shrouded by the cylinder bore.

305 is a tricky engine to build for power due to the small bore. It limits alot of choices.

The only good performance head on the market for a 305 is the trickflow alum. heads with the 1.94" valves which are like $1100

Other options would be to find a set of L30 305 vortec heads, or L31 350 vortec heads and on the 350 ones have them milled down at machine shop to around 60cc .

Then of course buy a vortec style intake.

If you have an edelbrock performer intake now then you have about the best 305 intake.. Do not waste your money on the performer EPS.

If your Q jet is in good working cond. it will make the same HP as an edelbrock, holley, barry grant, or any other carb. With carbs it's all in the tuning not the brand.

What is your timing set at? What is your timing curve? I'm willing to bet you big money that a $7 "recurve" kit, and 2 hours of your time will gain you 3 times the amount of power that those $400 aero heads will.

You need to map out your timing curve and set it with springs and weights (the $7 recurve kit) to start your advance right off idle about 1100 rpm or so and to have it fully advanced at 3000-3200 rpm.. Then set your timing to 36* total (with out vac advance hooked up) This will put idle timing around 14-17* btdc

 

Thanks Night Rider, I had figured I would pick up a good bit of power with those heads. I have found a few guys around here selling 5.7l vortec heads, but I was wondering, how much would it cost to have them machined for my 305, and what would I have to do to make them run with my hydraulic flat tappet cam? One guy offered to sell them for $175/pair, which seems pretty cheap. I have also seen 059 castings for the 305, but those are $700/pair, and still, I would need to modify them for my flat tappet cam, correct? I will accordingly be picking up a performer vortec intake as well of course. Then my question is, what cam will go well with these heads? A few people have recommended the CC XE256, and another reccomended the Lunati 60102 that I had already looked into, but both would require machine fork to the stock Vortec heads for enough lift, correct? Also, what recurve advance kit do I need?
Any advice would be great, thanks.

 

Summit K1103 would be a good cam choice

 

The vortec heads will need new 90-100# valve springs ($30), and have the heads milled down ($150) to give you your compression back.

Use fel pro 1094 head gaskets, fel pro MS98000T intake gaskets, summit K1102 or K1103 cam or An elgin cam that matches those specs.

Summit stage I or II vortec intake

And you will have you a nice budget friendly engine that gained maybe 50-60 HP over what you have now.

 

Will the heads still need milling if I get 059 castings? aren't they meant for a 305? And the 90-100# is installed seat pressure, correct?

 

You are correct. The 059 (L30 305 vortec) heads are 58cc chambers and will not need to be milled any.

The 906/062 (L31 350 vortec) heads are 60-64cc chambers (Most come in around 62cc) would drop a little compression and it would be wise to mill those if using on a 305.

Yes 90-100# installed seat pressure. Competition products has the best prices on valvetrain parts, and really good parts. I'm a big fan of Howards springs and really most of their parts.

 

Okay, thank you very much, i have begun looking for 059 casting heads

 

I am still looking for 059s, busy I found a set of 113s freshly machined and assembled for $500. Are these a good option? They are direct bolt ons, which is nice, and my compression will still be okay thanks to my flat top pistons. Could these and a nice intake/Cam make 300hp? Would they need port work?