Better Performance

[Car'n'Guitars]

Okay so what can you do to a 305 bolt-on wise that will get better performance? I don't replies like just get a 350 because I can't afford that at the current time. Because with these bolt-ons once I do get a 350 I can just transfer them over to it. I am also wondering when putting a bigger cam in wht all needs to be changed?

[THE "10" SILVERADO]

Probably the best bolt on would be headers.

Other than that, carb rebuild, new ignition system, etc.

[3r!c84]

did long tube headers on my 305. didnt realy notice anything change besides sound . like you said they transfer over when you go bigger. like me they are on my 400sbc now.

[Car'n'Guitars]

Originally Posted by 3r!c84

did long tube headers on my 305. didnt realy notice anything change besides sound . like you said they transfer over when you go bigger. like me they are on my 400sbc now.

Exactly but what type of things did you replace? With heads I've heard there are certain ones you want to stay away from with the 305?

[3r!c84]

Originally Posted by Car'n'Guitars

Exactly but what type of things did you replace? With heads I've heard there are certain ones you want to stay away from with the 305?

well you cant change to bigger heads on a 305. no other heads will fit on them because of the small bore size. only put headers on mine. and cleaned and rebuild the q jet. thats about all the performance your going to get out of it. save your money and build a 350 or what have you. hate to say it but 305s are a dog

[Car'n'Guitars]

Originally Posted by 3r!c84

well you cant change to bigger heads on a 305. no other heads will fit on them because of the small bore size. only put headers on mine. and cleaned and rebuild the q jet. thats about all the performance your going to get out of it. save your money and build a 350 or what have you. hate to say it but 305s are a dog

Yeah I know, what about cams on a 305?

[68Timber]

A cam, intake and carb would wake it up. No need to go big. You could reuse your carb to save some money. An Edelbrock Performer cam and intake would be a very good upgrade over stock.

[Car'n'Guitars]

Originally Posted by BRUISER

A cam, intake and carb would wake it up. No need to go big. You could reuse your carb to save some money. An Edelbrock Performer cam and intake would be a very good upgrade over stock.

Yeah I want to keep my carb, if I switch the cam, do I have to also change the pushrods?

[68Timber]

You keep the stock pushrods. You'd probably want to put a new timing set on since it'll be off anyway - if it hasn't been replaced yet. But you'd reuse everything else.

[Car'n'Guitars]

Originally Posted by BRUISER

You keep the stock pushrods. You'd probably want to put a new timing set on since it'll be off anyway - if it hasn't been replaced yet. But you'd reuse everything else.

Okay thanks that's exactly the kind of info I wanted. Do you have a model number for the cam?

[RandyP]

If you change the cam you need to replace the lifters. 1 cam, 16 lifters. Then you'll need to factor in to recharge the A/C (if you have it), coolant, water pump gasket, intake gasket, valve cover gaskets, assembly lube, break in oil and filter. This is guessing you know how to set valve lash and all the good stuff that comes along with replacing this stuff.

[Car'n'Guitars]

Originally Posted by RandyP

If you change the cam you need to replace the lifters. 1 cam, 16 lifters. Then you'll need to factor in to recharge the A/C (if you have it), coolant, water pump gasket, intake gasket, valve cover gaskets, assembly lube, break in oil and filter. This is guessing you know how to set valve lash and all the good stuff that comes along with replacing this stuff.

Why does the A/C need done?

[Car'n'Guitars]

How about this?

http://www.ebay.com/itm/Edelbrock-21...763#vi-content

[RandyP]

You'll either have to take the radiator/condenser out of the way or pull the motor. Either direction results in losing the A/C. Even by just removing the radiator/condenser you end up with a fairly good fight getting the old cam out and the new one in. We ended up cutting the vertical support on the core support to gain enough room, then welded it back up when done.

[Car'n'Guitars]

Originally Posted by RandyP

You'll either have to take the radiator/condenser out of the way or pull the motor. Either direction results in losing the A/C. Even by just removing the radiator/condenser you end up with a fairly good fight getting the old cam out and the new one in. We ended up cutting the vertical support on the core support to gain enough room, then welded it back up when done.

Well we would just pull the motor to do the work.

[RandyP]

Cams are usually about $100 and lifters are usually about $1 to $1.50 each, so that looks about right on price.

To bad you are not local to me or I'd make you a helluva deal on the cam and lifters we just took out of my sbc crate motor.

[Car'n'Guitars]

Yeah that's what I figured, thanks for the consideration.

[N2TRUX]

Talk to Gchemist. He built a pretty stout 305 and ran the snot out of it forever.

[bnoon]

Originally Posted by 3r!c84

well you cant change to bigger heads on a 305. no other heads will fit on them because of the small bore size. only put headers on mine. and cleaned and rebuild the q jet. thats about all the performance your going to get out of it. save your money and build a 350 or what have you. hate to say it but 305s are a dog

Not true. There are plenty of better flowing 305 heads out there. World Products even made Bowtie style ports for the 58cc heads that outflowed many 2.02/1.94 heads on the market, not to mention Vortec style heads, Corvette TPI heads (they're 58cc chambers and aluminum version of the IROC/TA TPI heads) and many others. You can also cut down many 64cc chamber heads with better port designs than the stock truck heads, then there's other 305 heads such as the 416 casting 305 H.O. and early TPI heads. There have also been several people to update to LS1 style stock valves that have worked very well in the 416 casting heads, not to mention there are MANY circle track classes that run 305 engines and the engine shops around here know how to make those little forgotten about mice scream.

I've done bolt-ons to many 305's over the years and cam/intake/headers are all well worth the effort. If you plan on pulling the engine it's easiest to spend the extra cash to build up a core 350 block and start with the better foundation, but if you never plan to pull it (or at least don't want to pull it for a long while) go ahead and build it up with the bolt-ons. I've had a Summit brand cam only update result in a 50 HP increase on a 305 TPI before and would imagine truck cam improvements would even be more due to the low lift/duration on stock truck cams.

[Car'n'Guitars]

Originally Posted by bnoon

Not true. There are plenty of better flowing 305 heads out there. World Products even made Bowtie style ports for the 58cc heads that outflowed many 2.02/1.94 heads on the market, not to mention Vortec style heads, Corvette TPI heads (they're 58cc chambers and aluminum version of the IROC/TA TPI heads) and many others. You can also cut down many 64cc chamber heads with better port designs than the stock truck heads, then there's other 305 heads such as the 416 casting 305 H.O. and early TPI heads. There have also been several people to update to LS1 style stock valves that have worked very well in the 416 casting heads, not to mention there are MANY circle track classes that run 305 engines and the engine shops around here know how to make those little forgotten about mice scream.

I've done bolt-ons to many 305's over the years and cam/intake/headers are all well worth the effort. If you plan on pulling the engine it's easiest to spend the extra cash to build up a core 350 block and start with the better foundation, but if you never plan to pull it (or at least don't want to pull it for a long while) go ahead and build it up with the bolt-ons. I've had a Summit brand cam only update result in a 50 HP increase on a 305 TPI before and would imagine truck cam improvements would even be more due to the low lift/duration on stock truck cams.

Okay thanks, I do plan to pull the engine to do the work, and also like I stated before I'm not going to switch to a 350 right now because I don't have all that extra cash. That's why I'm going with bolt-on so when I do get a 350 I can just transfer the parts over.

[riz]

If you have a 305 with less than 70k miles, expect to replace the cam right around that 70k mark. They are notorious for that. I replaced the cam on my 77 Impala right at the 70k mark. Not only is needed but a great time for an upgrade.

RIZ

[Car'n'Guitars]

Originally Posted by riz

If you have a 305 with less than 70k miles, expect to replace the cam right around that 70k mark. They are notorious for that. I replaced the cam on my 77 Impala right at the 70k mark. Not only is needed but a great time for an upgrade.

RIZ

Yeah I plan on replacing that regardless, but I'm gonna take a shot in the dark and say it has at least 170K on it.

[deth_1970]

in my experience, I have seen 305's with small valves, 1.84, so increasing them to 1.94 or 2.02's would help, better intake and carb, cam, plus headers would be the best way to go, bolt on wise, you do want to make sure you stay with 305 heads, because of the smaller combustion chamber, putting 76 cc heads on a 305 will change the compression ratio for the bad, from 8.5 or so to 6-7

[Car'n'Guitars]

Originally Posted by deth_1970

in my experience, I have seen 305's with small valves, 1.84, so increasing them to 1.94 or 2.02's would help, better intake and carb, cam, plus headers would be the best way to go, bolt on wise, you do want to make sure you stay with 305 heads, because of the smaller combustion chamber, putting 76 cc heads on a 305 will change the compression ratio for the bad, from 8.5 or so to 6-7

Okay so I should just keep the heads and just get them cleaned up?

[Firebirdjones]

How far are you planning to dig into this 305? How many miles are on it?

You've mentioned pulling the engine to do the work, and pulling heads to work on them? That's alot of work and effort just to stick that 305 back in there.

If you are really set on keeping that 305 for now, I'd stick to the simple stuff like headers, performer intake, MAYBE a tiny camshaft like the performer camshaft, and a timing chain while you're in there if it's still the plastic gear OEM piece.

Otherwise I'd leave well enough alone and keep the expenditures down in the $500 range and only spend time and money on things that will transfer to a better foundation later on. Those stock cylinder heads aren't one of them so I wouldn't waste my time with them. They won't do you any favors on a 350.

For the money and time spent, it really becomes more cost effective to get a simple 350 GM goodwrench engine (Jegs has them for $1400) and I've seen them as low as $1200 if you fish around.

I know it's not what you want to hear, but 350's are so darn cheap it's hard to justify too much time and money spent on a 305,,,,with how many miles??