72 Chey - temporary engine swap (need advise) - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Model 12 · 05-20-2002, 07:59 PM

My 72 350/175 TH350 is tired. VERY tired. I pulled my boat about 30 miles down I-40 near Knoxville and it was all it could do to make it to my destination. It's tired!

A friend has a 87 Chev 1/2 ton 305 truck (80k miles) that just got T-boned. I am considering buying the engine on the cheap and sticking it in the Chey, then rebuilding the orig 350 this winter, then sell the 305.

I had considered buying a crate motor, but that's going to be 1500 gibs minimum, and I still want to use the orig motor, rather than having it cluttering up the garage (unless it is just too worn).

The general plan is to use just the 305 long block mated to my intake, Q-Jet, fuel pump, distributor, ram horns, AC, PS pump and flexplate. Am I missing something? Are there some unknown issues about compatibility? Thoughts?

Thanks, Dave

Gordo · 05-20-2002, 08:09 PM

I put a 350 crate in a early 80's Blazer that had a 305. I swapped everything you mentioned over from the 305 to the 350. I would say the opposite would be the same and everything would bolt up.

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1971 C10 swb stepside 350/700R4/3.73posi
Killingworth, Connecticut

*Zkast* · 05-20-2002, 08:24 PM

Everything will work with the exception of the manifolds. mid 80's used a 7 bolt hole setup. You should have no trouble mounting your old manifolds onto the 305 heads but visa versa wouldnt work. Be sure to leave the 305 balancer on the 305 engine (timing marks will be in a different location) You'll look down through the water pump area to check timing on a 305.

Oh the other thing is temp sensors in the head, 305 would have smaller sensor holes (1/2" compared to the older 3/4") Just use your intake for coolant temp.

Beware, a 305 is no powerhouse lol. Might just as weak as your current engine.

------------------
Pictures and more...
piston@zkast.com
'71 LWB
350/350T, PS/PB
Special options? Yes, RUST... Need some?
------------------------------------------
Webmaster/Team owner
www.zkast.com
Garrett - Olathe, Kansas

[This message has been edited by Zkast (edited May 20, 2002).]

*racedvl* · 05-20-2002, 08:25 PM

An 87 should be fuel injected. Make sure the fuel pump mount is there and usable. Will the cam have the lobe for the fuel pump? You might need a electric fuel pump. But I'm not sure.

------------------

http://hometown.aol.com/racedvl/racedvl69index.html

Woodstock,IL.northwest of Chicago

It's not what you buy, it's what you build!!

I did not climb to the top of the food chain, to become a vegetarian.

For some pics of my truck.

**Tim Christian** · 05-20-2002, 08:41 PM

Welcome to the board! I live in Rogersville Tennessee up off I-81

------------------
67 GMC Stepside(UNDER CONSTRUCTION)
67 GMC Custom
67 Chevy C-30

*Zkast* · 05-20-2002, 08:44 PM

Good eye racedvl, dunno why but I thought I saw a 85 model listed.. ackk my eyes are old lol.

87 "Should" only have a block off plate for the fuel pump mounting but as racedvl stated, pull the cover and see if there is a hole drilled in the block.

------------------
Pictures and more...
piston@zkast.com
'71 LWB
350/350T, PS/PB
Special options? Yes, RUST... Need some?
------------------------------------------
Webmaster/Team owner
www.zkast.com
Garrett - Olathe, Kansas

Woody · 05-21-2002, 06:51 AM

I have a 85 305 in my truck now. It has been in there for about 4 yrs. I call it a nutless engine because it is so limp. It does fine, it's just that there is now throttle responce past 1/2 peddle. I have a T400 and 3.73 gears. It gets about 12 mpg no matter how you drive it. It was a easy swap since the 85 had a carb. Good Luck.

------------------
Woody
'69 Custom-10 Deluxe
Short Fleetside,Factory 350cid/TH400,A/C,PS,PB,Carpet
Coming soon 700R4, 350 Crate Engine, Pwr Disks...

Mike C · 05-21-2002, 06:54 AM

In adition to the exhaust manifolds, GM also changed the intake manifold manifold center bolts to a different angle in '87.

------------------
70 GMC 3/4 ton Sierra Grande 402/TH400
72 Jimmy 4WD 4spd 4" & 35's
64 Corvette Coupe
68 Camaro 'vert TPI & TH700
69 Z/28 355 12.6's @110
72 Datsun 240Z-ol' reliable

Model 12 · 05-21-2002, 10:32 AM

Thanks men...great insight (the intake bolts and/or cam lobe for the fuel pump may be a dealbuster!). I'll know more in a week or so.

Tim...drop me a Big Orange line and we'll talk trucks! Dave

------------------
If James Dean had a truck, it would be a Cheyenne Super...

*Randy70C-10* · 05-21-2002, 10:37 AM

You can get a Delco re-man engine for less than a rebuild. Advance sells then for around $799 here.

Blue68 · 05-22-2002, 03:04 PM

Too bad you aren't closer to Texas. I've got a '68 307 that runs good just cluttering up my garage. We all know it would bolt right in there. And I never had a problem pulling things with it. So what if it couldn't make the tires break loose w/3.73 rear gears.

I'm not so sure the exhaust manifolds are a problem (intake yes), unless it is a 305 issue. I bolted a 98 350 into my truck without any problems (except the need for an electric fuel pump and a vortech intake).

------------------
Frisco, Tx

'68 C-10 LWB, '98 Z-71 350 w/accessories (Serpentine), Edelbrock Performer, Edelbrock 1405 (600cfm) carb, GM HEI, CompCam Extreme 4x4 roller cam, Thorley Headers, Carter Electric Fuel Pump, Vintage Air, 700r4, 3.73, disc brakes and power steering upgrades.

Way too much money and time..But it's a hobby.

Duallie · 05-23-2002, 01:44 AM

1987 will also have the one-piece rear main seal and therefore a different flexplate or flywheel.

------------------
Just as if I knew what I was doin'

05-20-2002, 07:59 PM	#1
Model 12 Registered User Join Date: May 2002 Location: Knoxville, TN Posts: 20	72 Chey - temporary engine swap (need advise) My 72 350/175 TH350 is tired. VERY tired. I pulled my boat about 30 miles down I-40 near Knoxville and it was all it could do to make it to my destination. It's tired! A friend has a 87 Chev 1/2 ton 305 truck (80k miles) that just got T-boned. I am considering buying the engine on the cheap and sticking it in the Chey, then rebuilding the orig 350 this winter, then sell the 305. I had considered buying a crate motor, but that's going to be 1500 gibs minimum, and I still want to use the orig motor, rather than having it cluttering up the garage (unless it is just too worn). The general plan is to use just the 305 long block mated to my intake, Q-Jet, fuel pump, distributor, ram horns, AC, PS pump and flexplate. Am I missing something? Are there some unknown issues about compatibility? Thoughts? Thanks, Dave __________________ If James Dean had a truck, it would be a Cheyenne Super...

05-20-2002, 08:09 PM	#2
Gordo Registered User Join Date: Jan 2001 Location: Killingworth, CT. USA Posts: 3,378	I put a 350 crate in a early 80's Blazer that had a 305. I swapped everything you mentioned over from the 305 to the 350. I would say the opposite would be the same and everything would bolt up. ------------------ 1971 C10 swb stepside 350/700R4/3.73posi Killingworth, Connecticut __________________ 1971 C10 swb stepside 350/700R4/3.73posi (retired as of 4/22/03) 1998 S10 short bed 2002 S10 Blazer 1942 Oldsmobile 1958 Massey Harris Pony 1951 Wife Killingworth, Connecticut May those who love us, love us, any of those who do not love us, may God turn their hearts. And if God is unable to turn their hearts, may he turn their ankles so we may know them by their limping. A man who works with his hands is a laborer; a man who works with his hands and his brain is a craftsman; but a man who works with his hands and his brain and his heart is an artist.

05-21-2002, 06:54 AM	#8
Mike C Registered User Join Date: Dec 1999 Location: Austin, TX, USA Posts: 7,723	In adition to the exhaust manifolds, GM also changed the intake manifold manifold center bolts to a different angle in '87. ------------------ 70 GMC 3/4 ton Sierra Grande 402/TH400 72 Jimmy 4WD 4spd 4" & 35's 64 Corvette Coupe 68 Camaro 'vert TPI & TH700 69 Z/28 355 12.6's @110 72 Datsun 240Z-ol' reliable __________________ 44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax

05-21-2002, 10:32 AM	#9
Model 12 Registered User Join Date: May 2002 Location: Knoxville, TN Posts: 20	Thanks men...great insight (the intake bolts and/or cam lobe for the fuel pump may be a dealbuster!). I'll know more in a week or so. Tim...drop me a Big Orange line and we'll talk trucks! Dave ------------------ If James Dean had a truck, it would be a Cheyenne Super... __________________ If James Dean had a truck, it would be a Cheyenne Super...

05-22-2002, 03:04 PM	#11
Blue68 Registered User Join Date: Apr 2000 Location: Frisco, Tx, USA Posts: 606	Too bad you aren't closer to Texas. I've got a '68 307 that runs good just cluttering up my garage. We all know it would bolt right in there. And I never had a problem pulling things with it. So what if it couldn't make the tires break loose w/3.73 rear gears. I'm not so sure the exhaust manifolds are a problem (intake yes), unless it is a 305 issue. I bolted a 98 350 into my truck without any problems (except the need for an electric fuel pump and a vortech intake). ------------------ Frisco, Tx '68 C-10 LWB, '98 Z-71 350 w/accessories (Serpentine), Edelbrock Performer, Edelbrock 1405 (600cfm) carb, GM HEI, CompCam Extreme 4x4 roller cam, Thorley Headers, Carter Electric Fuel Pump, Vintage Air, 700r4, 3.73, disc brakes and power steering upgrades. Way too much money and time..But it's a hobby. __________________ http://home.comcast.net/~r.landrum/w...tos.html-.html '68 C-10 LWB, '98 Z-71 350 w/accessories (Serpentine), Edelbrock Performer, Edelbrock 1405 (600cfm) carb, GM HEI, CompCam Extreme 4x4 roller cam, Thorley Headers, Carter Electric Fuel Pump, Vintage Air, 700r4, 3.73, disc brakes and power steering upgrades.

05-20-2002, 08:24 PM	#3
Zkast Account Suspended Join Date: May 2002 Location: Olathe, Kansas Posts: 929	Everything will work with the exception of the manifolds. mid 80's used a 7 bolt hole setup. You should have no trouble mounting your old manifolds onto the 305 heads but visa versa wouldnt work. Be sure to leave the 305 balancer on the 305 engine (timing marks will be in a different location) You'll look down through the water pump area to check timing on a 305. Oh the other thing is temp sensors in the head, 305 would have smaller sensor holes (1/2" compared to the older 3/4") Just use your intake for coolant temp. Beware, a 305 is no powerhouse lol. Might just as weak as your current engine. ------------------ Pictures and more... piston@zkast.com '71 LWB 350/350T, PS/PB Special options? Yes, RUST... Need some? ------------------------------------------ Webmaster/Team owner www.zkast.com Garrett - Olathe, Kansas [This message has been edited by Zkast (edited May 20, 2002).]

05-20-2002, 08:25 PM	#4
racedvl Account Suspended Join Date: Jan 2000 Location: Woodstock, IL Posts: 7,020	An 87 should be fuel injected. Make sure the fuel pump mount is there and usable. Will the cam have the lobe for the fuel pump? You might need a electric fuel pump. But I'm not sure. ------------------ http://hometown.aol.com/racedvl/racedvl69index.html Woodstock,IL.northwest of Chicago It's not what you buy, it's what you build!! I did not climb to the top of the food chain, to become a vegetarian. For some pics of my truck.

05-20-2002, 08:41 PM	#5
Tim Christian Senior Member Join Date: Dec 1999 Location: TN/VA Posts: 6,388	Welcome to the board! I live in Rogersville Tennessee up off I-81 ------------------ 67 GMC Stepside(UNDER CONSTRUCTION) 67 GMC Custom 67 Chevy C-30

05-20-2002, 08:44 PM	#6
Zkast Account Suspended Join Date: May 2002 Location: Olathe, Kansas Posts: 929	Good eye racedvl, dunno why but I thought I saw a 85 model listed.. ackk my eyes are old lol. 87 "Should" only have a block off plate for the fuel pump mounting but as racedvl stated, pull the cover and see if there is a hole drilled in the block. ------------------ Pictures and more... piston@zkast.com '71 LWB 350/350T, PS/PB Special options? Yes, RUST... Need some? ------------------------------------------ Webmaster/Team owner www.zkast.com Garrett - Olathe, Kansas

05-21-2002, 06:51 AM	#7
Woody Registered User Join Date: Feb 2000 Location: Georgetown, KY, USA Posts: 631	I have a 85 305 in my truck now. It has been in there for about 4 yrs. I call it a nutless engine because it is so limp. It does fine, it's just that there is now throttle responce past 1/2 peddle. I have a T400 and 3.73 gears. It gets about 12 mpg no matter how you drive it. It was a easy swap since the 85 had a carb. Good Luck. ------------------ Woody '69 Custom-10 Deluxe Short Fleetside,Factory 350cid/TH400,A/C,PS,PB,Carpet Coming soon 700R4, 350 Crate Engine, Pwr Disks...

05-21-2002, 10:37 AM	#10
Randy70C-10 Account Suspended Join Date: Mar 2001 Location: Virginia Beach, Va. U.S.A. Posts: 15,320	You can get a Delco re-man engine for less than a rebuild. Advance sells then for around $799 here.

05-23-2002, 01:44 AM	#12
Duallie Registered User Join Date: Feb 2001 Location: Nikiski, Alaska Posts: 477	1987 will also have the one-piece rear main seal and therefore a different flexplate or flywheel. ------------------ Just as if I knew what I was doin' __________________ Just as if I knew what I was doin'

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