JKRacing

So just to make this clear I did say 305 not 350 just for those who are curious. I am one who is entirely behind powerhousing the "Restrictive" 305. What I want to do is get the most out of my 305 without putting forced induction on it. I have heard that I can bore the stock LG4 block out to match the numbers of a 327 motor. Is this true because if so I would like to know what these numbers are and how I can go about doing so. Or is it not worth the time and money as there is a better idea for the 305. Again I dont want to hear get a 350 your wasting your time with a 305. Ihave a 305 I dont have a 350 so thats what I want to work on. I know there is a build thread for a 370+ LG4 block motor which I have looked into. But I am wondering if I can get better then that.

sofakingdom

iTrader: (1)

Then you heard wrong.

The 327 uses the same block dimensions as the 350 (4.000" bore). You can't bore the 305 block out ANYWHERE NEAR that far.

It is not worth the time or money to rebuild a 305 in the interest of "more power", PERIOD. Any thing you can do to it that increases its cubic inches, besides buying a 350 core, costs more than simply buying a 350 core to work on instead. Anything you do to a 350 gives you about 15% more for your money since (350 - 305) / 305 = ~.15. Anything you do to a 305 costs the same as doing it to a 350 (boring, new pistons, cleanup, whatever) except it gives you 15% less for your money. For all of these reasons, it is not sensible to work on a 305 short block, if power is what you're interested. Heads, cams, exhaust, bolt-ons, ... sure; ANYTHING to the short block however, is a mistake. Throw it in the trash and get a block with a larger bore.

Atilla the Fun

Sofa's right. You'll find a thousand threads on this, and they all reach the same conclusion: Put a turbo on it, or replace it with something better.

86LG4Bird

iTrader: (1)

A 100 shot of nitrous does wonders
That's the ONLY mod mine gets until it surrenders its real estate to more cubes

JKRacing

I really. I dont like when people dont listen. I understand the 350 is better. However this isnt my question HAVE a 305. I DONT HAVE a 350. I guess what i should tell everybody is that the car isnt staying with this motor. The motor is going in something way lighter then this. But i am in a competition with a mustang hos 5.0 bored out stroker motor against my 305. No forced induction allowed. So putting a 350 in will eat him alive unfairly.

Dougs91

Well since you're going against a 5.0 Ford with your 305 you're already hosed. The stang 5.0 has a 4" bore and the valves are not shrouded like they are in the 305. Therefore they can run larger valves and have improved flow in the heads. You have your work cut out for you.

urbanhunter44

iTrader: (3)

If he's got a stroker 302 a better match against his would be a 327. Get a 350 block and a 3.25" stroke crank. Or even make a chevy 302 with the same block and the 283 3" crank.

Bottom line you need a 4" bore. The 305 doesn't have one, it's 3.740 IIRC.

JKRacing

OK. Well still leaves the question of what can I do to make the 305 better. I'm not switching motors until I have a 400 cid block set up cause that is the motor I am planning on swapping into it. However the rules of the competition is best of a 305 TA against best of a 302 Stang. No forced induction. No NOS. Anything else is fair game. This motor will be going into an 85 Chevy S10 once my cousin and I have raced on the track with the two cars. He thinks my TA will out do his mustang. But he wants to try. Now let me tell you a little bit about what the motor I have has. Its got an Accel high efficiency coil on top of distributor. The distributor has been recurved. It has the 1406 HO heads. 8.8 mm spark plug wires. And a tuned 600 cfm edelbrock carb accompanied by a 3/4 inch throttle body spacer on top of stock 305 intake. Dyno'd was 210 on 4 pulls at +4 degrees tdc and 215 on 3 pulls at +10 degrees tdc. However pushed oil at higher timing mark. I have raced against a 260 HP 280zx turbo datsun and had him through 2nd gear til his turbo kicked in as he had longer 2nd gear ratio in his car. I am running a 3.73 9 bolt rear end and built thm350 transmission. And torque rating was 270 ft lb through all pulls. It didn't change through timing changes. I do not have dyno results anymore. The ex accidentally through them out when she cleaned out the car after we split. So with that in mind now. Someone help me with a direction I can take from here. I have heard a set of vortec heads and a port and polish can increase that another 25+ horse exact numbers aren't 100% accurate as the guy I talked to cannot remember exact numbers. Someone please give me ideas for the 305 no other motor please

JKRacing

Wow I said 1406 heads that was totally wrong that's the edelbrock Carb the heads are 416 HO's which I am going to do the porting on once the motors out.

ASE doc

First off, let me condition what I say by telling you that I would be the first to tell you to dump the 305. If anything, build a DZ302 clone by destroking the 4.00" bore block down to 3.00". This would produce the same cubes as the Ford 5.0 and you could make some serious high rev power from it. That being said, I will try to help you with your limited current goals.

First, the smaller cubes will want to make power at higher rpms. You are restricted by the smaller bore but not done in by it. If you want to use any larger valve than the 1.94s of the HO heads, you will have to radius the cylinder tops to prevent interference with the valves. The smaller bores also reduce cylinder filling by shrouding the valves. None the less, the key to high rev power is air movement. An Edelbrock Performer RPM at the least or even a Victor Jr. intake on top of some good heads with a suitable cam. The Performer RPM will work with the Vortecs' 1.99 intake valves. The Victor will want a more aggressive cam and larger valves(2.02 intake minimum). The cam for the dual plane intake would be in the range of 223-230 at .050 and around .500 gross lift. I prefer hyd roller for more lift under the curve but a flat tappet will work if that's all you can do. The Victor Jr will want more like 240 degrees and .520 lift. You could run even more lobe with the Victor but you will run into drivability issues, especially with a carb on the street. The camn specs that I have called out will already be challenge to tune for the street. Increased advance at idle will help.

Vortecs are a good head for the money and when ported they can support good power. Atilla the fun did a thread on porting of the Vortec head. You should be able to find it through a search for "Vortec heads". An even better head would be something like the AFR 185 or 195. The Victor single plane intake will want the bigger intake ports. The good thing about running the AFR 195s is that they could also be used the 400 block that you plan on swapping in later.

sofakingdom

iTrader: (1)

As already said, look at heads, cam, exhaust, GEARS, converter, and stuff like that. EVERYTHING BUT the short block. DO NOT touch the short block, unless you are willing to throw money away; which if buying a $100 core to "amplify" your money with is too much to spend, then wasting $1500 MINIMUM on rebuilding a short block that will be a disappointment no matter what you do, is CERTAINLY out of the question.

It is not worth wasting time and money on a 305 short block PERIOD. End of story. You will regret it no matter how much bluster and bravado and all the rest of that, you can come up with.

I'd also suggest getting the "rules" of your little "competition" adjusted to something that makes sense; like, instead of "equal" cubes, make it, equal CID-to-weight ratio.

Failing that, minimize the expense of th emotor, and concentrate on weight reduction. ESPECIALLY if you have a Firebird.