want to convert 305 tpi system to 350

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Nov 28, 2002 | 12:03 AM

87iroc305tpi

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From: South Jersey

want to convert 305 tpi system to 350

i got an 87 iroc with a 305 tpi i want to get a brand new 350 motor, i was wondering what i would have to do to put a 305 tpi system into a 350 motor that was designed for using a carb.and one more thing, when i was searching for motors it said
"foruse up to 1985" could some explain to me what that means. thanks alot

Nov 28, 2002 | 02:28 AM

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305 and 350 TPI parts (intake) are all the same deal. The injectors, knock sensor, and chip in the ecm are different. Not real hard to 'convert' from one to the other.

Nov 28, 2002 | 08:40 AM

Jim85IROC

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From: Readsboro, VT

Car: 85 IROC-Z / 88 GTA

Engine: 403 LSx (Pending) / 355 Tuned Port

Transmission: T56 Magnum (Pending) / T5

Axle/Gears: 3.42 / ?

The ESC is different as well, although I doubt its effect is substantial.

Nov 28, 2002 | 12:12 PM

90Iroc

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Joined: Oct 1999

Posts: 271

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From: Greenwood, IN USA

Car: 1990 Iroc/Z

Engine: LB9 305 TPI

Transmission: Borg Warner 5 speed

I think that the "for use up to 1985" refers to the main seals. Is that right? That 350 probably has a two piece seal instead of a one piece.

Nov 28, 2002 | 04:16 PM

Der91Z

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From: Maryland

Car: 1993 Toyota Supra

Engine: Inline 6

Transmission: 6 Speed

Axle/Gears: 3.13

be sure to check the heads to make sure your intake will go on there properly. the pre-86 heads are different on the center intake bolt angles. You will have to have your intake slotted i believe to put them on the older heads if they are the older heads. If not, there will be no problems. Also besure to check if the motor is a 2 piece rear main seal or a 1 piece rear main seal.