how to tell if it is a 305 or 350? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

BLUE THUNDER · 05-24-2007, 12:20 AM

so i got my 72 really cheap. the guy i got it from said he didn't know what engine it had. can i find out by the firing order or do i need to find the casting numbers on the block? if i do need to go the casting number route what should i look for? thanks.

jhow66 · 05-24-2007, 12:48 AM

Look behind the head on driver's side. There will be a # on the block. Get this and look it up here:
www.mortec.com

67Steven · 05-24-2007, 11:11 AM

Firing order is the same on all the small block chevy engines if I remember correctly,

1-8-4-3-6-5-7-2.

mattstoc · 05-24-2007, 11:47 AM

You said you go the blazer really cheap: if you don't mind me asking, what was really cheap?

RckyMntnKng · 05-24-2007, 12:06 PM

Change the Oil and see if it holds 5 or 5.7 liters?

Blizz · 05-24-2007, 04:52 PM

$1,500

Jtrux · 05-24-2007, 05:49 PM

Easy, pull the heads off and check the bore. 4.00 it's a 350, 3.75 (?) and it's a 305.

LUV2XCLR8 · 05-24-2007, 06:32 PM

Will it haul ass? (This would be the quickest way to answer it)

Kurt L · 05-24-2007, 07:15 PM

haha luv,that's good

Jason915 · 05-24-2007, 09:19 PM

sometimes it's hard to see the casting numbers on the block, I'd pull a valve cover and start with the head cast numbers that'd give you an idea.

BLUE THUNDER · 05-24-2007, 11:18 PM

well i was underneath it a little while ago, and i couldnt see a darn thing. i saw some numbers on the passenger side of the block, but nothing on the lt side. blizz was correct, i paid $1500 bucks for it. it'a a 72 cst with a 305 or 350, turbo 350, np 205 posi trac rear, little rust, origional tow hooks, lift and 35's. not bad at all. the electrical still works for the most part. i do need a lift gate and a gas tank for it. i love my new toy.

bouncytruck · 05-25-2007, 12:44 AM

Well, if it is the original engine, it is a 350. In 72, the only options were the 6 and the 350.

HuggerCST · 05-25-2007, 09:39 AM

Quote:

Originally Posted by BLUE THUNDER

well i was underneath it a little while ago, and i couldnt see a darn thing. i saw some numbers on the passenger side of the block, but nothing on the lt side. blizz was correct, i paid $1500 bucks for it. it'a a 72 cst with a 305 or 350, turbo 350, np 205 posi trac rear, little rust, origional tow hooks, lift and 35's. not bad at all. the electrical still works for the most part. i do need a lift gate and a gas tank for it. i love my new toy.

Sounds like a deal! Those block numbers will be cast into the top of the block, behind the driver side head.

Jtrux · 05-26-2007, 01:18 PM

Quote:

Originally Posted by BLUE THUNDER

well i was underneath it a little while ago, and i couldnt see a darn thing. i saw some numbers on the passenger side of the block, but nothing on the lt side. blizz was correct, i paid $1500 bucks for it. it'a a 72 cst with a 305 or 350, turbo 350, np 205 posi trac rear, little rust, origional tow hooks, lift and 35's. not bad at all. the electrical still works for the most part. i do need a lift gate and a gas tank for it. i love my new toy.

BTW, I told Tom about your name, Blue Thunder, so expect to get some sort of criticism over it. Oh and when can I come see this thing?

BLUE THUNDER · 05-27-2007, 01:10 PM

Dude, i did catch some from tom, but that's to be expected. i scored some front signal housings, lenses, a door handle and a h/l bezel at pick-n-pull yesterday for $20.00. Let's see about getting the blazers together sometime in the next couple of weeks. Btw, congrats on the new job.

Jtrux · 05-30-2007, 02:39 PM

Quote:

Originally Posted by BLUE THUNDER

Dude, i did catch some from tom, but that's to be expected. i scored some front signal housings, lenses, a door handle and a h/l bezel at pick-n-pull yesterday for $20.00. Let's see about getting the blazers together sometime in the next couple of weeks. Btw, congrats on the new job.

Thanks.

Critter · 05-30-2007, 02:49 PM

Quote:

Originally Posted by BLUE THUNDER

Btw, congrats on the new job.

I agree...now get some welding skills!!!

05-24-2007, 12:20 AM	#1
BLUE THUNDER Registered User Join Date: May 2007 Location: San Antonio Posts: 993	how to tell if it is a 305 or 350? so i got my 72 really cheap. the guy i got it from said he didn't know what engine it had. can i find out by the firing order or do i need to find the casting numbers on the block? if i do need to go the casting number route what should i look for? thanks.

05-24-2007, 12:48 AM	#2
jhow66 Registered User Join Date: Jun 2002 Location: Knoxville Tenn. Posts: 3,058	Re: how to tell if it is a 305 or 350? Look behind the head on driver's side. There will be a # on the block. Get this and look it up here: www.mortec.com __________________ 56 Chevy Bel-Air 2dr. HT (purchased new) 71 Chevy Cheyenne SWB PU (502HO) 65 GMC short bed step--work in progress and my gofer

05-24-2007, 11:11 AM	#3
67Steven Registered User Join Date: Mar 2007 Location: Oregon City Posts: 228	Re: how to tell if it is a 305 or 350? Firing order is the same on all the small block chevy engines if I remember correctly, 1-8-4-3-6-5-7-2.

05-24-2007, 11:47 AM	#4
mattstoc Registered User Join Date: Jan 2003 Location: Anna, TX Posts: 30	Re: how to tell if it is a 305 or 350? You said you go the blazer really cheap: if you don't mind me asking, what was really cheap? __________________ Matt Stockton mattstoc@dfwair.net 972-924-2293

05-24-2007, 12:06 PM	#5
RckyMntnKng Registered User Join Date: Apr 2007 Location: Meridian, Idaho Posts: 316	Re: how to tell if it is a 305 or 350? Change the Oil and see if it holds 5 or 5.7 liters? __________________ 71 Jimmy: D60/14BFF, 9"F/11"B Lift, 350-350-203-205, Crossover Hydro steering, Beadlocks, Tube stuff and the bottomless cooler

05-24-2007, 04:52 PM	#6
Blizz Registered User Join Date: May 2006 Location: San Antonio, Texas Posts: 372	Re: how to tell if it is a 305 or 350? $1,500 __________________ '72 K5 CST Blazer 4x4 in perpetual progress '96 2dr Tahoe 4x4 daily driver, Black Bear Performance tune, 285-75-16 Nitto Grapplers, Magnaflow muffler, K&N Air filter, Bilstein Shocks.........E-fan, DT Tri Y or Pacesetter LTs coming soon

05-24-2007, 05:49 PM	#7
Jtrux I'm a poor spectator Join Date: Aug 2006 Location: San Antonio, Tx Posts: 2,287	Re: how to tell if it is a 305 or 350? Easy, pull the heads off and check the bore. 4.00 it's a 350, 3.75 (?) and it's a 305. __________________ 2006 Jeep Unlimited IMPACT ORANGE 1993 Chevy 2500 4x4 ExCab LWB 454/NV4500 Tow rig 1977 Ford F100 2x4 LWB 1st truck I owned, still have it!!! 1979 Ford F150 4x4 SWB Built Ford Tough!!! 1971 Chevy Blazer 350 / SM465 / NP205 UNDER CONSTRUCTION Soon to have a LQ4 6.0!!!

05-24-2007, 06:32 PM	#8
LUV2XCLR8 The LuvShack Garage Join Date: Jan 2004 Location: Maple Grove, TN (West Side) Posts: 30,468	Re: how to tell if it is a 305 or 350? Will it haul ass? (This would be the quickest way to answer it) __________________ Owner/Op: "TN Classic Transport Carriers" The Toy: "Square Vette" 72 Hybrid Blazer Toy Barn: "LuvShack" 40 x 60 x 20 Shop Tow Piggy:"Maddy" 88 Silverado 3500 Hauler: "Feathers" 14 Aluma 8218T

05-24-2007, 07:15 PM	#9
Kurt L Senior Member Join Date: May 2003 Location: ne florida Posts: 2,665	Re: how to tell if it is a 305 or 350? haha luv,that's good

05-24-2007, 09:19 PM	#10
Jason915 Registered User Join Date: Jan 2005 Location: Colorado Springs Posts: 693	Re: how to tell if it is a 305 or 350? sometimes it's hard to see the casting numbers on the block, I'd pull a valve cover and start with the head cast numbers that'd give you an idea. __________________ 1971 GMC K1500 SWB Fleetside, 4" skyjacker softride and, 14 Bolt FF, HD Dana 44 4.10's 1970 K5 TBI conversion lifted etc SOLD 1968 C20 camper truck SOLD “To ban guns because criminals use them is to tell the innocent and law-abiding that their rights and liberties depend not on their own conduct, but on the conduct of the guilty and the lawless.” Jeff Snyder

05-24-2007, 11:18 PM	#11
BLUE THUNDER Registered User Join Date: May 2007 Location: San Antonio Posts: 993	Re: how to tell if it is a 305 or 350? well i was underneath it a little while ago, and i couldnt see a darn thing. i saw some numbers on the passenger side of the block, but nothing on the lt side. blizz was correct, i paid $1500 bucks for it. it'a a 72 cst with a 305 or 350, turbo 350, np 205 posi trac rear, little rust, origional tow hooks, lift and 35's. not bad at all. the electrical still works for the most part. i do need a lift gate and a gas tank for it. i love my new toy.

05-25-2007, 12:44 AM	#12
bouncytruck SKINNY TIRES RULE! Join Date: Sep 2001 Location: Bothell, WA Posts: 11,038	Re: how to tell if it is a 305 or 350? Well, if it is the original engine, it is a 350. In 72, the only options were the 6 and the 350. __________________ bouncytruck 1972 K5 The Hauler 1994 K1500 Suburban The Daily2010 Kia Soul Wife's Ride2014 Fiat 500L

05-27-2007, 01:10 PM	#15
BLUE THUNDER Registered User Join Date: May 2007 Location: San Antonio Posts: 993	Re: how to tell if it is a 305 or 350? Dude, i did catch some from tom, but that's to be expected. i scored some front signal housings, lenses, a door handle and a h/l bezel at pick-n-pull yesterday for $20.00. Let's see about getting the blazers together sometime in the next couple of weeks. Btw, congrats on the new job.

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