327 w/350 or 305 heads - The 1947 - Present Chevrolet & GMC Truck Message Board Network

hotrodtroy · 03-16-2004, 02:02 PM

currently I have a 327 running 350 heads. What is the difference between running my current heads or switching them out with a set of later model 305 heads. will the change get me more HP or torque and / or better gas milage? I'm a body and fender guy and haven't gotten into the motors too much.

Any info would be appriciated.
P.S. All parts are stock.

MrGoodpliers · 03-16-2004, 04:14 PM

I've never used 305 heads on a 350, but I hear that it's a good combination on a budget. I think they have very small combustion chambers, which will raise your compression- and small runners as well. My guess (and it's a guess, look at my name

) is that you will find that you get great torque, but not much high-end hp.

jmanz69 · 03-16-2004, 06:47 PM

I had them on my 327 and they make awsome torque but not a lot up top for HP. Fun to drive around town with. Had to run premium gas though. I had 11:1 comp. I sold them when I decided to go FI. I would recommend it if you want to have a stoplight racer and not a highway racer.

dubie · 03-16-2004, 06:52 PM

I have 60cc chamber 305 heads on my 350. I haven't even fired the engine, but I wanted it to be torquey, and I was told this would do the trick. We should find out in the coming weeks

jmanz69 · 03-16-2004, 06:54 PM

Mine were 58cc heads. Had larger valves put in too. I think 1.88 intake or something. The guy who built the engine did it for me years ago.

68cajun · 03-16-2004, 11:30 PM

I have a set of 305 vortec 059 heads 58cc i would like to sell. Fresh valve job and resurfacing, ready to bolt on.

Longhorn Man · 03-17-2004, 12:22 AM

I had non vortec 58cc heads with the tiny valves on a stock 350, and it ran like crap. Had to run 93 octain, and ignition at 2 degrees just to get it to run, and it still didn't run very well. With a bottle of octain booster, I was abl to bump it to a whopping 4 degrees BTDC.
The truck was a dog, and would hardly breath once I got it up to 3500 RPM, which limited my speed to about 80 MPH.

03-16-2004, 02:02 PM	#1
hotrodtroy Registered User Join Date: Feb 2004 Location: Colorado Springs, CO Posts: 138	327 w/350 or 305 heads currently I have a 327 running 350 heads. What is the difference between running my current heads or switching them out with a set of later model 305 heads. will the change get me more HP or torque and / or better gas milage? I'm a body and fender guy and haven't gotten into the motors too much. Any info would be appriciated. P.S. All parts are stock. __________________ '72 C-10 w/ '68 Large Journal 327cu.in. "It's o.k. to dream about what you want to do, until you start doing what you are meant to do." Line from "The Rookie"

03-16-2004, 04:14 PM	#2
MrGoodpliers Registered User Join Date: May 2002 Location: Gainesville, Georgia Posts: 704	I've never used 305 heads on a 350, but I hear that it's a good combination on a budget. I think they have very small combustion chambers, which will raise your compression- and small runners as well. My guess (and it's a guess, look at my name ) is that you will find that you get great torque, but not much high-end hp. __________________ We made Oklahoma a little after 3, Randy & his brother Bob & my old GMC...

03-16-2004, 06:52 PM	#4
dubie Registered User Join Date: May 2000 Location: Flin Flon, Manitoba, Canada Posts: 8,853	I have 60cc chamber 305 heads on my 350. I haven't even fired the engine, but I wanted it to be torquey, and I was told this would do the trick. We should find out in the coming weeks __________________ My name's Tim and I'm a truckaholic My 56 Chevy shop truck build http://67-72chevytrucks.com/vboard/s...d.php?t=562795

03-16-2004, 11:30 PM	#6
68cajun 68 C/10 Join Date: Oct 2003 Location: Houma Louisiana Posts: 367	I have a set of 305 vortec 059 heads 58cc i would like to sell. Fresh valve job and resurfacing, ready to bolt on. __________________ (2009) GMC Sierra Denali 6.2 AWD (67 C/10 fleetside SWB) (2018GMC Yukon Denali) Wifes Car

03-16-2004, 06:47 PM	#3
jmanz69 Careful, they attack... Join Date: Aug 2001 Location: Waterford, MI, USA Posts: 1,107	I had them on my 327 and they make awsome torque but not a lot up top for HP. Fun to drive around town with. Had to run premium gas though. I had 11:1 comp. I sold them when I decided to go FI. I would recommend it if you want to have a stoplight racer and not a highway racer.

03-16-2004, 06:54 PM	#5
jmanz69 Careful, they attack... Join Date: Aug 2001 Location: Waterford, MI, USA Posts: 1,107	Mine were 58cc heads. Had larger valves put in too. I think 1.88 intake or something. The guy who built the engine did it for me years ago.

03-17-2004, 12:22 AM	#7
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	I had non vortec 58cc heads with the tiny valves on a stock 350, and it ran like crap. Had to run 93 octain, and ignition at 2 degrees just to get it to run, and it still didn't run very well. With a bottle of octain booster, I was abl to bump it to a whopping 4 degrees BTDC. The truck was a dog, and would hardly breath once I got it up to 3500 RPM, which limited my speed to about 80 MPH.



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