Any hot 305s here?

[turbo350]

Yeah I know don't bother with a 305, go with at least a 350. I've read and heard that before. Just wondering if anyone here has a "hot" 305. I have a really nice 305 that I pulled outta my boat. Its factory rated at 225 hp. I've already got a baby blower from a previous project. I'm thinking with some decent pistons,heads, etc I could run mild boost and have about 300 to 350 horsies. Not looking to go drag racing but might be a fun street combo for my truck. Anyone got a nice 305 thats quick for the street?

[skyreep1]

I have a 307 in my 71 c10 that blew a 70's 350 Monte Carlo outta the water, totally stock. I would'nt say dont bother, I was just lookin at the HP charts and after 71 the horses just bottom out. My 71 307 has about 25 less HP than a 79 with a 440 big block.

['72customdeluxe]

Originally Posted by skyreep1

I have a 307 in my 71 c10 that blew a 70's 350 Monte Carlo outta the water, totally stock. I would'nt say dont bother, I was just lookin at the HP charts and after 71 the horses just bottom out. My 71 307 has about 25 less HP than a 79 with a 440 big block.

440 chrysler? That sounds like you're comparing your gross horsepower to later net horsepower. Big difference. Most people say not to bother with a 305 because a 350's 4" bore breathes better. But it's not breathing by itself, under boost your heads matter more. You could go with forged pistons and heads ment for larger engines (bigger than 58 cc's, what's normally on 305's) for a really low compression then boost the crap out of it.. Put the smallest top and biggest bottom pulley they make for it on there. What is it, a Weiand/B&M 144? One thing I would think about is water jacket rot being a boat motor. Did it use fresh water or a heat exchanger for cooling? As far as fast 305's in general, a hot set up now is vortec heads, mild cam, and a good intake manifold for just over 350 horsepower and lb/ft of torque

[turbo350]

Water jacket looks good, it was a fresh water engine that was maintained very good. Pulled it for more power in the boat. I'm not too up on the newer Vortec heads. Any suggestions which ones would be good for a blower application? Yeah, its the 177 Weiand.

['72customdeluxe]

what's your budget for heads look like? I would for sure put money towards good rod bolts and forged pistons in a boosted app. Then you could rpm it too. With the 177 weiand you could make 450 horses with good heads i bet

[skyreep1]

I'm not really sure what I'm lookin at but no, its a 454BB (typo) on either a 79 chevy or GMC. Excuse my mechanical illiteracy. All I know is that it says

"1971 8-307 2bbl 215HP@4800RPM and 305ft.lbs.@2800RPM 3.875x3.250 bore&stroke and 9.0:1 compression

VS

1979 8-454 4bbl 205HP@3600RPM and 350ft.lbs.@2500RPM 4.250x4.000 Bore&stroke 8.0:1 compression"

I would appreciate some further explanation. Is the 454 still faster since it's @1000 less RPM? and am I right to say that our torque are only 45ft.lbs. from being the same??

[turbo350]

Originally Posted by '72customdeluxe

what's your budget for heads look like? I would for sure put money towards good rod bolts and forged pistons in a boosted app. Then you could rpm it too. With the 177 weiand you could make 450 horses with good heads i bet

Is it possible to get some good heads for this application under say $600-$700?? I just need some suggestions on which ones to get, ie: Vortec or others? As you stated I have to keep in mind I need to get some good forged pistons, rods, etc. I would be happy with 350-400 horse, but 450ish might really put a smile on my face.

Skyreep1,

I don't want to hi-jack my own thread but here is the horsepower rating method explained:

SAE horsepower
[edit] SAE gross horsepower

Prior to the 1972 model year, American automakers rated and advertised their engines in brake horsepower (bhp), frequently referred to as SAE gross horsepower, because it was measured in accord with the protocols defined in SAE standards J245 and J1995. As with other brake horsepower test protocols, SAE gross hp was measured using a stock test engine, generally running with few belt-driven accessories and sometimes fitted with long tube (test headers) in lieu of the OEM exhaust manifolds. The atmospheric correction standards for barometric pressure, humidity and temperature for testing were relatively idealistic.
[edit] SAE net horsepower

In the United States, the term bhp fell into disuse in 1971-72, as automakers began to quote power in terms of SAE net horsepower in accord with SAE standard J1349. Like SAE gross and other brake horsepower protocols, SAE Net hp is measured at the engine's crankshaft, and so does not account for transmission losses. However, the SAE net hp testing protocol calls for standard production-type belt-driven accessories, air cleaner, emission controls, exhaust system, and other power-consuming accessories. This produces ratings in closer alignment with the power produced by the engine as it is actually configured and sold.
[edit] SAE certified horsepower

In 2005, the SAE introduced a new test protocol for engine horsepower and torque.[12] The new protocol eliminates some of the flexibility in power measurement, and requires an independent observer present when engines are measured. The test is voluntary, but engines completing it can be advertised as SAE-certified.

A few manufacturers such as Honda and Toyota switched to the new ratings immediately, with multi-directional results; the rated output of Cadillac's supercharged Northstar V8 jumped from 440 hp (330 kW) to 469 hp (350 kW) under the new tests, while the rating for Toyota's Camry 3.0 L 1MZ-FE V6 fell from 210 hp (160 kW) to 190 horsepower (140 kW). Much of the drop can be attributed to Toyota now rating engines on 87 octane, compared to Lexus which uses 91 octane. This is why the same 3.3 L 3MZ-FE V6 engine in the Lexus ES330 and Camry SE V6 did not show equal declines. The ES330 and Camry SE V6 were previously rated at 225 hp but the ES330 dropped to 218 hp while the Camry declined to 210 hp. The first engine certified under the new program was the 7.0 L LS7 used in the 2006 Chevrolet Corvette Z06. Certified power rose slightly from 500 hp (370 kW) to 505 hp (377 kW).
[edit]

[shortbed70]

I've rode in a car that had a stroked (383) kit 305 cant remember cubic in. maybe 335 but ran very well and couldnt tell it was a 305. It pulled harder then my 350 did in the same type of car same gearing and trans. If you can get a set of heads if you go with a blower get some 180+cc heads but the problem lies in the valve shrouding with the small bore motor.

['72customdeluxe]

Yeah, enginekits.com has a 335 striker kit. Don't know if forged pistons are available for that application though. You might try some Patriot performance vortec heads. They are drilled for both old style and vortec heads so your supercharger will bolt up. .575 lift springs, detonation resistant 64cc chambers, guide plates,screw in studs, really good flow numbers. All for 600 a pair. If the 64cc chambers will work, the heads alone should get you 350 horsepower naturally aspirated. If that is your power goal you might sell the supercharger and have a quick somewhat fuel efficient 305. But if you're like me you'll want the torque of the blower a naturally aspirated 335 rotating assembly from enginekits.com plus those vortec heads sounds like a solid setup. But if you want it boosted I would do a forged piston low compression 305 and use the highest boost pulley set up you can. That would be a torque monster.

[Rodms]

I'll post some specs tomorrow on a 40 over 305 and its a bad dude ,I don't remember all the parts I put in it,but it will fly in a 82 4x4!

[turbo350]

A buddy has some stock smog heads from a '77 350. he thinks they are the 882 heads (1.94 valves), low compression which would work with the little blower. I know the 882s don't quite flow like certain newer heads but I still may be able to get 375, maybe even close to 400 hp with these heads depending on how much boost I run. I understand some say they are crack prone but that is supposedly due to excessive heat. But if you don't let it get too hot they should be fine. There is a trick to prepping them that helps minimize the overheating I guess. I only bring up these 882s because I can get them for free. I guess I could buy newer better flowing heads but thats gonna cost xxx for maybe an extra 25-50 hp versus the 882s??

[Super73]

I'm a firm believer that heads and cam make a motor regardless of if it's a NA / N20 / Turbo / Blower motor. You could be leaving more than you think with a crap set of heads. Think about this one second. A motor is a huge air pump, the more efficiant it is, the better results you get.

Now, I'm not saying go find a head with ridiculous flow numbers that are all hoged out. What I'm trying to say is figure out what you really want out of this motor, and what your budget really is. Then start working backwards. You could always run the 882's until you had enough money to put another set of heads on. In that case, I would build the rest of the combo around aftermarket heads, so your not buying parts twice. It may not be optimum for the 882 heads, but when you put a different set of heads on, it will really wake up.

You will also run less boost and make the same or more power with a better flowing intake track.

[Super73]

just doinng a quick figuring in Performance Trends Engine Analyzer..

3.875 bore
3.25 stroke
882 heads with 8.5-1 cr
Weiand 177 with a belt ratio of 2
1 5/8 30" headers
91 octane at 165*

224/224 with .510/.510 ground on a 110icl / 110 lsa
440ftlbs peaking at 4,100-4,400 flat through those rpms
439hp at 5,500


236/236 .510/.510 104icl/105lsa
443ftlbs @ 4,350
441hp @ 6,000

['72customdeluxe]

I don't think that you can run 76cc chambers (what the 882's have) on the small bore. I think you'd get almost the same power selling off your supercharger and going with afr heads or the like as opposed to smogger heads and the supercharger. Better mileage too.

[turbo350]

Originally Posted by '72customdeluxe

I don't think that you can run 76cc chambers (what the 882's have) on the small bore.

Hmmm, I will have to check into this. If the 882s won't work any suggestions on similar priced stock type heads that would work?, remember I need low compression, preferably not much higher than 8:0:1.

As for the blower I'm partial to keeping it the sound alone is pretty wicked, not to mention the boost setting you back in the seat.

[Captainfab]

Not trying to nitpick but that bore & stroke is for a 307. A 305 is 3.750 bore with a 3.48 stroke.

Originally Posted by Super73

just doinng a quick figuring in Performance Trends Engine Analyzer..

3.875 bore
3.25 stroke
882 heads with 8.5-1 cr
Weiand 177 with a belt ratio of 2
1 5/8 30" headers
91 octane at 165*

224/224 with .510/.510 ground on a 110icl / 110 lsa
440ftlbs peaking at 4,100-4,400 flat through those rpms
439hp at 5,500


236/236 .510/.510 104icl/105lsa
443ftlbs @ 4,350
441hp @ 6,000

[C-10 simplex]

i was just curious---couldn't any 305 be "made" into a 350 by boring? Because essentially these two engines are basically similar---same stroke, etc.


i know there are differences such as heads, but talking about the basic block.

[cableguy0]

you cannot bore it far enough to make it a 350. its not the same block

[Pyrotechnic]

Given a running 305 that had a lot of life left in it for a decent price or even free, I wouldn't mind doing simple/cheap things to it to make more power. A $100 white box cam and lifters, intake, headers, etc are good things that will help out. If you can get the whole thing running and making good power for a bargain, then it's a good deal.

I wouldn't go for an all out ground up build on a 305 though. Spending that same money on a 350 block will get you the more motor for the exact same price. With that said, to stay in a reasonable budget with this 305 you will want to use at least the short block AS IS.