305 V8 performance?

If you want to try to prove something - figure out how to build the 305 to prove the naysayers wrong. Wheels777 has some interesting insights into 305 potential Maybe you can Message him?

I would say build a 350. compared to a 305 with the same work (intake, exhaust, cam, lifters, rockers, etc.) the 350 will give you about 40-50 more hp - cubic inches- plain and simple.

I say go one further - the engine bay is huge! get a 454 from a junkyard Suburban - hopefully later-model with FI - and roast the tires! The same motor mounts are used - the trucks came with big-blocks stock - remember the 454SS?

Face it - It's a truck. While they can be made to corner - they aren't laid out to be cornering machines. They aren't made out to be drag machines either as they have all their weight over the front wheels. They can be MADE to corner and they can be MADE to hook-up - but it's an uphill battle.

There is something to be said about watching a truck do a wheel stand or in a perfect four wheel drift - defying the laws of logical physics. But isn't that what we do? Cheat physics?

have a 350 done up like I did for my 89 suburban, drop it in, enjoy.

still think it would be fun to see what a MS or eqivelent (i know GM ECU's are pretty well 100% hacked) and doing a turbo setup using the POS TBI lol... just to see what would happen...

I guess if you can't go with bigger valves, you can focus on the details around them. Have the heads reworked so that they flow better and get a three-angle valve job. The holes might not be any bigger, but the air will flow better.

Oh, and definitely get some Nitrous Oxide! Lots of it!

If the budget is tight, and you aren't looking at trying to full kill at the race track, tweak the 305 on a budget. Vortec heads, better exhaust, computer tuning, etc. You won't have the torqe of the 350, but you'll have more power than before. Vortec heads are cheap. So is aftermarket exhaust systems for these trucks (Summit, Jegs, etc)Then save some money for a crate 350. Then sell the 305 to someone with a S10 or Camaro.

seeker589 wrote: drift

maybe that's what I should do instead of auto-x....

In reply to ManofFewWords:

My 2006 GMC has a little 305 in it and I'm getting ready to throw a set of headers and flowmaster exhaust on it, I already put the cold air intake on and am waiting for my upgrade chips. I don't want to go fast, I just wanna sound good as I look! Howie

Hotelfox wrote: In reply to ManofFewWords: My 2006 GMC has a little 305 in it and I'm getting ready to throw a set of headers and flowmaster exhaust on it, I already put the cold air intake on and am waiting for my upgrade chips. I don't want to go fast, I just wanna sound good as I look! Howie

the 305 was last used in the 98 model year in trucks and the 99 model year in suburbans and vans. after that point, they went LS and haven't looked back..

which brings me to my suggestion for the OP- get a 5.3 and put it in there. they can be had for cheaper than a 350- and definitely less than it would cost to make a 305 perform- and can be bolted right in with available parts..

Now the 305 is a great motor to just drive. The one in my 92 Camaro has never had the valve covers off of it, and its got damn near 170K miles. It's just now starting to smoke on startup, and I've beat the PISS out of that car.

As far as just a running, driving motor its very hard to beat a 305, in my personal experience.

Now as far as building power, I'm with Derrick here and say go LS. They are built in numbers well into the sixth digit, and can be found for cheap. Car craft took one and with just a carb intake, valve spring upgrade and cam swap added a bunch of power.

LS FTW!</a

Also, stay away from the 4.8, same problems as the 305, cept smaller.

It always amzes me at the amount of myths floating aroun don the chevy 5.0.

Just a FYI for anyone that cares. The class that I race in Camaro mustang challenge requires a 305 in the thirg gen in CMC1 and we just opened up the 350 for the 3rg gen in cmc 2.

Anyway. With box stock vortech heads, Ebelbrock TPI lower manifold, 1.6 rockers and shorty headers guys are seing right around 270 hp to the wheels and 320 tq.

None of those parts cost more for a 305 than a 350. They are the same parts.

Anyway not trying to tell anyone that a 305 is a great motor and better than a 350. However they are not as bad as every internet jockey thinks they are.

Parts list for a mild inexpensive 305 TPI.

Parts List: Intake - Edel 3817 - 469.95 from Summit Heads - 12558060 - 309.95ea - 619.90 from Summit Head bolts - QES72856 - 23.95ea - 47.90 - Fel-Pro - Summit Head Gaskets - Fel-Pro 1094 - 21.88ea - 43.76 from Summit TPI Base to Runner Gaskets Edel 3866 - 33.95 - Summit Intake gaskets - QMS93318 - FelPro - 29.95 - Summit Thermo gasket - 1.25 - FelPro - Summit Rockers – Used Crane Gold $175 – CMC bulletin Board Header Locks - 8911 - 41.95 - Stage 8 - Summit Header reducer - 11035 - Hooker - 9.95 - Amazon Headers – 2460HKR - Hooker - 165.95 - Summit Exhaust tubing –$39.00 Motion Motorsports EGR Block off Plate – home made

272 hp 325 tq

confuZion3 wrote: Oh, and definitely get some Nitrous Oxide! Lots of it!

Paging Mr. Pseudosport...

The Pseudosport name comes from his high school chariot: a beat to hell 305-powered 1986 Monte Carlo Luxury Sport that was the unfortunate recipient of many modifications, including its Monte SS nose. He named it the Pseudosport. It LOVED nitrous, right up until it spit parts out the exhaust!!! I could write a book about that car (especially about what our circle of friends calls "The Story"), but that will be for another thread.

305 is not the best starting point but it can still be a fun motor for cheap. I’d add a cheap set of headers, mild cam to work with the stock computer, converter, and gears. If you want any more power then that then its time to upgrade to a 350.

CaptainSpaulding wrote: ....right around 270 hp to the wheels and 320 tq. 272 hp 325 tq

Sweeet

They work...they are not 350s...but they are SBCs. Bolt ons = cheap fun.

wheels777 wrote:

CaptainSpaulding wrote: ....right around 270 hp to the wheels and 320 tq. 272 hp 325 tq

Sweeet They work...they are not 350s...but they are SBCs. Bolt ons = cheap fun.

I agree, it is a good deal, and great cheap availability of parts. Except that you can gain an easy 40-60 hp at that level by switching to another equally inexpensive block with no weight penalty at all. Why? Heck, I wouldn't stop at 350. 400s are still out there at around the same cost. At that level, you're getting another 100 hp for free. Completely for free, providing you know how to drill a hole.

CaptainSpaulding wrote: Just a FYI for anyone that cares. The class that I race in Camaro mustang challenge requires a 305 in the thirg gen in CMC1 and we just opened up the 350 for the 3rg gen in cmc 2. Parts list for a mild inexpensive 305 TPI. Parts List: Intake - Edel 3817 - 469.95 from Summit Heads - 12558060 - 309.95ea - 619.90 from Summit Head bolts - QES72856 - 23.95ea - 47.90 - Fel-Pro - Summit Head Gaskets - Fel-Pro 1094 - 21.88ea - 43.76 from Summit TPI Base to Runner Gaskets Edel 3866 - 33.95 - Summit Intake gaskets - QMS93318 - FelPro - 29.95 - Summit Thermo gasket - 1.25 - FelPro - Summit Rockers – Used Crane Gold $175 – CMC bulletin Board Header Locks - 8911 - 41.95 - Stage 8 - Summit Header reducer - 11035 - Hooker - 9.95 - Amazon Headers – 2460HKR - Hooker - 165.95 - Summit Exhaust tubing –$39.00 Motion Motorsports EGR Block off Plate – home made 272 hp 325 tq

Awesome, I love following recipes.

Would it be reasonable to think a motor built to this spec could sell for okay money if I indeed felt the insatiable need for more powah?

alex wrote:

CaptainSpaulding wrote: Just a FYI for anyone that cares. The class that I race in Camaro mustang challenge requires a 305 in the thirg gen in CMC1 and we just opened up the 350 for the 3rg gen in cmc 2. Parts list for a mild inexpensive 305 TPI. Parts List: Intake - Edel 3817 - 469.95 from Summit Heads - 12558060 - 309.95ea - 619.90 from Summit Head bolts - QES72856 - 23.95ea - 47.90 - Fel-Pro - Summit Head Gaskets - Fel-Pro 1094 - 21.88ea - 43.76 from Summit TPI Base to Runner Gaskets Edel 3866 - 33.95 - Summit Intake gaskets - QMS93318 - FelPro - 29.95 - Summit Thermo gasket - 1.25 - FelPro - Summit Rockers – Used Crane Gold $175 – CMC bulletin Board Header Locks - 8911 - 41.95 - Stage 8 - Summit Header reducer - 11035 - Hooker - 9.95 - Amazon Headers – 2460HKR - Hooker - 165.95 - Summit Exhaust tubing –$39.00 Motion Motorsports EGR Block off Plate – home made 272 hp 325 tq

Awesome, I love following recipes. Would it be reasonable to think a motor built to this spec could sell for okay money if I indeed felt the insatiable need for more powah?

I'd say no, it wouldn't be reasonable to think you could sell it for real money. On the other hand, with that recipe, you're not doing much to it that couldn't be pulled off and swapped onto a 350...

Here are my latest thoughts on the 305:

Before owning my latest 305, I never considered the 305 to be anything more than a get-around engine. I still don't...but now I'm completely whelmed with the one I have. What's different? What's different is that now I have a van that I have NO DESIRE to hotrod. Ever. That made a 305 the perfect engine for it. It'll pull a trailer with a car on it at 70 mph on the freeway...I can't really ask anything more of it. I realize this is answering a question you didn't ask, but if you can think of the truck as an appliance and not a hot-rod (which is, realistically what you'll use it for 99.9% of the time, I recon)...the 305 will hit the spot nicely.

Clem

alex wrote: Yeah, I'm starting a new thread, guys. I recently bought an '88 GMC 1/2 ton with a 305 as a work truck. The motor is healthy, but a little breathless. Not too surprising, considering I've seen dyno numbers around 190 ponies as stock. Eventually, in addition to a reliable work truck, I'd like to make this into a bit of an entertaining sleeper - drop it a couple inches, fat sway bars (recommendations on both are welcome, off topic), and a torquey motor. So, I'm looking for streetable, bolt-ons. I'm happy to do anything that doesn't involve actually pulling the motor. And I realize the answer might be: swap in a 350. If that's your argument, convince me that it's worth the extra effort.

The answer is, without a doubt, swap in a 350. I've been where you are, recently. The answer, furthermore, is throw the TBI away and start over for induction. I put a balanced 350 with flat-tops in my '93 with a set of Vortec heads, a Crower Baja Beast cam (this cam will make your truck feel like a 454SS, only it will keep breathing past 3000 rpm), the GMPP TBI Vortec intake, and a Holley 670 TBI. When the engine got warmed up it was unbelievably quick for a 4600 lb truck. It was a nightmare when the engine was cold though. It fouled spark plugs like crazy, fouled the catalytic converter. After two years and multiple dyno shops I gave up and put a 670 Street Avenger manual choke carb on it and replaced the 4L60E with a 700R4. I still don't have the truck back on the road for having to get around wiring issues, and I parked it for the induction swap in 2008.

My advice, having the advantage of hindsight: put in a stock replacement 350 and a nice-sounding exhaust, make it look nice, and drive it. Then start elsewhere to make something fast.

alex wrote: These are compelling arguments. Thanks, guys. I'm definitely giving the 350 more serious consideration than before. It's not that I'm against it, by any means. It's just that I like underdog motors. But I also like a high power:money ratio. Food for thought, for sure. Given what Dan said about the camshafts, it seems like a swap is in order as 'preventive maintenance.' Heh, heh. If I were going to swap cams, what other relatively cheap bolt ons would complement the cam that would serve to wake up the poor old 305? (And just out of curiosity, Dan, what mileage did that problem rear its head?)

The camshaft problem crops up on any engine with a flat-tappet camshaft as modern oils (in the more recent API updates) no longer have the anti-wear additives (zinc primarily, IIRC) to prevent the cams from wiping on the lifters and eating themselves.

The solution for this is to use a motor oil that has these additives, or to add them when you change your oil. Lots of speed shops (and I'm pretty sure Summit and Jeg's carry it too) sell a ZDDP additive that street oils are missing. Valvoline's race oil has this additive, as well as Valvoline Syn-Power synthetic. Additionally, Shell's "Rotella T" truck oil still has it as well.

By the way, if you're thinking about swapping the cam and keeping the TBI... don't. Even mild cams drive those things bonkers. Either carb it or swap to a TPI intake and a MAF system from a 3rd gen or get really creative and do an 0411 LS computer swap. This is an EXTENSIVE rewire (and not a cheap swap all-around) that only the brave should attempt but you end up with a VERY tuneable setup. You'll also need the distributor out of a '96 or newer truck with the cam position sensor to make this work. There's a company called EFI Connection you should check out if you're interested in doing this.

Car Craft just covered the 305 vs 350 debate in their recent issue. Bottom line: more power, less money = 350. Lots of technical reasoning for it though.

Ambitious_But_Rubbish wrote:

alex wrote: These are compelling arguments. Thanks, guys. I'm definitely giving the 350 more serious consideration than before. It's not that I'm against it, by any means. It's just that I like underdog motors. But I also like a high power:money ratio. Food for thought, for sure. Given what Dan said about the camshafts, it seems like a swap is in order as 'preventive maintenance.' Heh, heh. If I were going to swap cams, what other relatively cheap bolt ons would complement the cam that would serve to wake up the poor old 305? (And just out of curiosity, Dan, what mileage did that problem rear its head?)

The camshaft problem crops up on any engine with a flat-tappet camshaft as modern oils (in the more recent API updates) no longer have the anti-wear additives (zinc primarily, IIRC) to prevent the cams from wiping on the lifters and eating themselves. The solution for this is to use a motor oil that has these additives, or to add them when you change your oil. Lots of speed shops (and I'm pretty sure Summit and Jeg's carry it too) sell a ZDDP additive that street oils are missing. Valvoline's race oil has this additive, as well as Valvoline Syn-Power synthetic. Additionally, Shell's "Rotella T" truck oil still has it as well. By the way, if you're thinking about swapping the cam and keeping the TBI... don't. Even mild cams drive those things bonkers. Either carb it or swap to a TPI intake and a MAF system from a 3rd gen or get really creative and do an 0411 LS computer swap. This is an EXTENSIVE rewire (and not a cheap swap all-around) that only the brave should attempt but you end up with a VERY tuneable setup. You'll also need the distributor out of a '96 or newer truck with the cam position sensor to make this work. There's a company called EFI Connection you should check out if you're interested in doing this.

From what I have heard there were also some very questionable offshore lifters on the market under several different brand names that caused a lot of the ream issues. There are lifter manufacturers who don't seem to be affected by the zinc issue as others.

What I take away from these discussions is, if you've got a 305 that needs rebuilding and it needs pistons (meaning, it's not a low-mile engine, poor compression etc) then go find a 350 to build. If you want a Chevrolet V8 and can get a 305 for free or very close to free, go with it, otherwise go find a 350 to build.

In theory the 305 should be able to get better mileage not only through lower cubic inches to fill with fuel, but a smaller bore diameter so there's less "edge" for the fuel to hide in during a combustion event. If outright power is the goal then the 305 is definitely at a disadvantage for those same reasons.

pres589 wrote: What I take away from these discussions is, if you've got a 305 that needs rebuilding and it needs pistons (meaning, it's not a low-mile engine, poor compression etc) then go find a 350 to build. If you want a Chevrolet V8 and can get a 305 for free or very close to free, go with it, otherwise go find a 350 to build. In theory the 305 should be able to get better mileage not only through lower cubic inches to fill with fuel, but a smaller bore diameter so there's less "edge" for the fuel to hide in during a combustion event. If outright power is the goal then the 305 is definitely at a disadvantage for those same reasons.

That is correct. If you just want people to see a Chevrolet V8 when you open the hood and have something that will reliably move around under its own power, a 305 is fine. You just give up a LOT of performance due to the small bore versus a 350.

Incidentally, I think 305's are a popular choice for i/o boat engines because they provide V8 sound and V8 torque for getting up on plane with a full load at a reduced fuel consumption rate vs a 350.

Incidentally, I've never seen a 305 that is a "high-compression" engine. The '80's Monte Carlo SS engines (RPO L69) were the only "performance" versions made I'm aware of and have a whopping 9.5:1 compression ratio, which is about all that the iron heads of the day could comfortably do on 91-octane gasoline. These were basically the Cross-Fire 'Vette engines with computer-controlled Quadrajet carburetors. Most of them were the RPO LG4 with 8.4:1 compression. Smog era poo.

And to think, I was convinced my SBC days were behind me!!

Ambitious_But_Rubbish wrote: If you just want people to see a Chevrolet V8 when you open the hood and have something that will reliably move around under its own power, a 305 is fine. You just give up a LOT of performance due to the small bore versus a 350.

This is horrible. I remember our '88 C-1500 truck with a 305 was rated at a massive 10 hp less than the 350 version. 10 whole horsepower! I'm losing my mind the difference is so drastic.

And what is the word 'just' doing in there? Nice cheap power, tons and tons and tons of aftermarket, just has nothing to do with it.

What ARE the largest valves you can run in a 305? I know it's not 2.02. Will the 1.94 valves fit the heads?

The only thing hyper-expensive about the 305 that I've seen are the pistons. That is to say, there are no $200 popups available for it, pistons cost as much as all those other engines' pistons do!