305 to 350 compatability - The 1947 - Present Chevrolet & GMC Truck Message Board Network

oirebit84 · 11-18-2008, 09:01 PM

I have an 87 gmc sierra with a tbi 305. I have a 350 engine short block out of a 94 chevy k2500 tbi. will the heads from the 305 work on the 350? What else would i have to change? I know i would have to put injectors for a 350 in it. but would the comp be the same? any input would be greatly appreciated! Thanks!

**LEEVON** · 11-18-2008, 09:39 PM

no the heads won't work. check around on Craigslist, a set of 350TBI heads could be had for maybe $100 and remanufactured heads can be had from builders for a few hundred. Use the 350 injectors, get a new EPROM from the donor truck if it's the same drivetrain or somewhere like www.tbichips.com. Everything else is a direct swap. If the later truck has a serpentine set up use it too. Let us know how it goes.

oirebit84 · 11-19-2008, 08:32 AM

HI Thanks. What is the difference between the 350 heads and 305 heads. Is an 87 350 short block identical to a 94 350 short block? Thanks!

**LEEVON** · 11-19-2008, 10:55 AM

I believe the ports are much smaller on the 305 heads, hopefully someone else will chime in on this, i just know they won't work. The blocks will be the same, assuming the '87 block is a one-piece rear main / roller block.

11-18-2008, 09:01 PM	#1
oirebit84 Registered User Join Date: Mar 2008 Location: Rhinebeck Ny Posts: 23	305 to 350 compatability I have an 87 gmc sierra with a tbi 305. I have a 350 engine short block out of a 94 chevy k2500 tbi. will the heads from the 305 work on the 350? What else would i have to change? I know i would have to put injectors for a 350 in it. but would the comp be the same? any input would be greatly appreciated! Thanks!

11-18-2008, 09:39 PM	#2
LEEVON Moderator Join Date: Jul 2006 Location: Ozark, MO Posts: 4,893	Re: 305 to 350 compatability no the heads won't work. check around on Craigslist, a set of 350TBI heads could be had for maybe $100 and remanufactured heads can be had from builders for a few hundred. Use the 350 injectors, get a new EPROM from the donor truck if it's the same drivetrain or somewhere like www.tbichips.com. Everything else is a direct swap. If the later truck has a serpentine set up use it too. Let us know how it goes. __________________ '86 GMC C30 Crew ~ '86 C20 Crew ~ '79 K15 Sierra Grande ~ '76 Blazer 2wd ~ '74K10 ~ '71 Cheyenne swb ~'50 3100 bagged ~ '80 Wife ~ Late model kids

11-19-2008, 08:32 AM	#3
oirebit84 Registered User Join Date: Mar 2008 Location: Rhinebeck Ny Posts: 23	Re: 305 to 350 compatability HI Thanks. What is the difference between the 350 heads and 305 heads. Is an 87 350 short block identical to a 94 350 short block? Thanks!

11-19-2008, 10:55 AM	#4
LEEVON Moderator Join Date: Jul 2006 Location: Ozark, MO Posts: 4,893	Re: 305 to 350 compatability I believe the ports are much smaller on the 305 heads, hopefully someone else will chime in on this, i just know they won't work. The blocks will be the same, assuming the '87 block is a one-piece rear main / roller block. __________________ '86 GMC C30 Crew ~ '86 C20 Crew ~ '79 K15 Sierra Grande ~ '76 Blazer 2wd ~ '74K10 ~ '71 Cheyenne swb ~'50 3100 bagged ~ '80 Wife ~ Late model kids



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