305 To 350 Swap Problem


profox02
03-14-2005, 03:32 PM
Over The Weekend I Tried To Swap My 305 With A 350 Crate...but The Intake Manifold From The 305 Would Not Fit...whats Up Wit Dat...i Thought I Could Swap It...i Need To Find Out What Year I Can Use The 350....is There A Web Site I Can Search The # Off The Engine???...what Else Can I Do???...the Intake Manifold's Four Bolt Holes In The Middle Wount Line Up...i Talked To A Guy At Autozone..he Said The '91 305 Manifold Will Not Fit Onthe New 2000 350...the Guy I Bought It From Said It Was For The 88-98 Chevy Truck C/k Series...the Number I Found One The 350 Is 0066088...is This The Right Number??? Help......

2000CAYukon
03-14-2005, 08:41 PM
That does not look like a casting number. Check out this page to find out what block you have: http://www.mortec.com/location.htm

It would also help to know what year your 305 is from.

//2000CAYukon

amac209
03-14-2005, 08:50 PM
the reason it won't fit is you got the wrong engine. the 350 crate engine you bought if for a 96-98 chev meaning it has vortec heads. what you can do is buy an intake from gm performance parts that is a tbi- vortec conversion. also you will need to get an egr valve, tube & manifold from a 96+ at a junkyard. a 350 with vortec heads makes quite a bit more power and torque than a regular 350 tbi. you will also need bigger injectors from a 350 and a different prom chip. i would get an aftermarket chip calibrated for the new engine.

profox02
03-15-2005, 09:22 AM
the 305 is a '91.....also are the blocks the same???...and if so can i swap the heads and then put on my intake manifold???...after buying this engine I am running really low on $....so i need to do it cheap.

profox02
03-15-2005, 12:18 PM
i just went to your "mortec" website and found the casting # and it says..."10066038"(this is the number i got off the engine)...350....year '92..Goodwrench crate motor, 2-piece rear seal

it says its a '92 engine....so shouldn't just swap over???....

2000CAYukon
03-15-2005, 12:47 PM
Your 91 block is a 1 piece seal. The other block is a 2 piece seal (older gen 1 block). Therefore, the flex plate (auto) or flywheel (manual) is not interchangeable. Not sure if the starter is the same or not. Did you get a flexplate or flywheel with the new block?

The heads from your TBI engine can be swapped to the 2 piece seal block.

//2000CAYukon

profox02
03-15-2005, 01:00 PM
I GOT A FLY WHEEL...ALSO WHAT IS A "350 Target Master/Goodwrench crate motor"???...THE CASTING NUMBER IS 10066038 OR 10066036 THE LAST NUMBER ON THE BLOCK IS A "6" OR AN "8", I CANT TELL...

profox02
03-15-2005, 01:07 PM
Another Question On This Swap..what Head Gaskets Do I Get For A 350 With 305 Heads???the Guy At Autozone Said They Are The Same...so I Got 305 Head Gaskets But Havent Put Them On Yet...so Any Info Would Help..thx

2000CAYukon
03-15-2005, 03:02 PM
Another Question On This Swap..what Head Gaskets Do I Get For A 350 With 305 Heads???the Guy At Autozone Said They Are The Same...so I Got 305 Head Gaskets But Havent Put Them On Yet...so Any Info Would Help..thx

profox02,
I owe you an apology. Your 305 heads will fit on the 350 block; however, you need to check what you resulting compression ratio will be. This is because the 305 heads have a smaller combustion chamber than the 350 heads. The result could be that your engine will require very high octane gas. You should talk to a machine shop or engine builder to see what will happen with the 305 heads on the 350 block.

I am not sure if anyone makes a TBI intake manifold for the older style heads (which is on your Target Master crate engine) but that may be a better way to go since you are on a budget.

The Goodwrench/Target Master crate engine are replacement engines that you can buy from GM.

//2000CAYukon

profox02
03-15-2005, 03:42 PM
THE LAST NUMBER LOOKS LIKE A "6" OR AN "8"..I THINK ITS A "8"..AND THIS ONE IS A '92....AND THE "6" IS THE "Target Master crate engine"....I THINK IM GONNA GO THIS WAY....SO WOULD U KNOW WHAT PARTS I SHOULD GET..305 OR 350 EXAMPLE--HEAD GASKETS, INTAKE GASKETS, SPARK PLUGS, KNOCK SENSOR....

2000CAYukon
03-15-2005, 05:27 PM
THE LAST NUMBER LOOKS LIKE A "6" OR AN "8"..I THINK ITS A "8"..AND THIS ONE IS A '92....AND THE "6" IS THE "Target Master crate engine"....I THINK IM GONNA GO THIS WAY....SO WOULD U KNOW WHAT PARTS I SHOULD GET..305 OR 350 EXAMPLE--HEAD GASKETS, INTAKE GASKETS, SPARK PLUGS, KNOCK SENSOR....

A "6" is probably a 2 bolt main vs the "8" being a 4 bolt main. Both engines are designed for pre-1987 vehicles. 1987 is when they went with a different bolt pattern for the intake and when they changed to a 1 piece rear seal.

The head gaskets should be the same for both blocks. The intake gaskets will depend on which intake you are using. The spark plugs also depend on which heads you are using (the 305 heads or the ones on the crate engine). You will need a knock sensor from a 350 (87-95 gm truck with the L05 engine)

I am still concerned about compression rations if you use the 305 heads on the 350 block.

Here is some info that may be helpful:
http://www.thirdgen.org/techbb2/showthread.php?threadid=275616
http://www.thirdgen.org/techbb2/showthread.php?threadid=283391
http://www.thirdgen.org/techbb2/showthread.php?threadid=281933

The last link above will be interesting to you because it talks about using a 4-bbl intake with TBI.

//2000CAYukon

profox02
03-15-2005, 06:20 PM
Thanks For All The Info....ill Let U Guys Kno
w How It Turns Out.. :evillol:

acewelderman
03-15-2005, 07:57 PM
Ive seen guys just egg shape the manifold holes & it seems to work good!Thats goes for non vortec heads only.

profox02
03-16-2005, 09:09 AM
Yeah We Though About That..but We Decided That It Might Not Get A Good Seal So Were Going To Swap The Heads And Go With The Higher Compresion

2000CAYukon
03-16-2005, 04:58 PM
Yeah We Though About That..but We Decided That It Might Not Get A Good Seal So Were Going To Swap The Heads And Go With The Higher Compresion

You might try a thicker head gasket to help increase the volumn. Every little bit will help.

//2000CAYukon

profox02
03-16-2005, 05:02 PM
I Just Posted This New...but What Is The Torque Specs For The Heads...i Know The Sequence...but Not The Specs..

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