warrenp Posted August 11, 2003 Share Posted August 11, 2003 hey, i just bought a 1990 TPI MOTOR. it's a 305 from a pontiac ecu wiring harness and even alternater for $500 i'm almost 100% sure that 305 tpi and 350 tpi is the same???? cuz i'm hoping this 305 motor i just bought had big valve heads so i can use a 4 bolt 350 block i have. Quote Link to comment Share on other sites More sharing options...
dmyntti Posted August 11, 2003 Share Posted August 11, 2003 I believe all of the 305's had smaller valves. Big valves don't fit in the bore. Another thing to consider is that the 305's had smaller injectors than the 350's so you may need an upgrade. Quote Link to comment Share on other sites More sharing options...
warrenp Posted August 11, 2003 Author Share Posted August 11, 2003 yeah i figured i may need an ecu upgrade too for a 350???? about the big valve heads some 305s had biger vavle heads tha 350's that was about the only good thing about them. Quote Link to comment Share on other sites More sharing options...
Mike C Posted August 12, 2003 Share Posted August 12, 2003 The only 350 that has smaller valves than a 305 would be from a heavy duty truck. One that uses thicker valve stems in order to better shed heat into the guides. Most "late model" small blocks have 1.95/1.50 valves. And that is all that will fit on a 305s smaller bore. The 305 heads will have 58cc chambers which is worth about 2/3 a point of compression on a 350. As noted, the 305 uses smaller injectors than the 350. The ECM should be the same, but the eprom will be different. Quote Link to comment Share on other sites More sharing options...
fl327 Posted August 12, 2003 Share Posted August 12, 2003 Ive driven a stock 350tpi with 305 harness and inj in a Iroc. Same thing as far as I could feel. Torque comes at really low Rpm, then stops pulling at like 4k, geez maybe earlier?? Ive driven 350 tpi before, a roller cam year even, man Same feeling. Its not the engine, its the efi setup-in terms of Cfm it equals and functions like a 2 barrell. I like these engines for swaps into a Z, the donor IROC or firebirds with tpi always have an OD trans, can run 87 all day long, fuel injection, and OK power in the smaller chassis. I also dig the salt and pepper sound of a TPI engine. Quote Link to comment Share on other sites More sharing options...
Guest the_dj Posted August 12, 2003 Share Posted August 12, 2003 Boy does it ever stop pulling at 4K. You really have to shift at around 4200. That I did not like. Quote Link to comment Share on other sites More sharing options...
warrenp Posted August 12, 2003 Author Share Posted August 12, 2003 whats the eprom? i know more about nissans than i do about chevys so i guess i gotta learn all this. Quote Link to comment Share on other sites More sharing options...
Pathogen Posted August 13, 2003 Share Posted August 13, 2003 Eprom = Erasable Programmable Read Only Memory The EPROM stores the software and will need to be reprogrammed not sure about TPI but I know LT1 peeps are using Tuner cat or you can just get someone else to reprogram it for you. Quote Link to comment Share on other sites More sharing options...
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