Is the 305 TPI or the 350 TPI a better motor build-up? Also, what is the difference besides the obvious difference in cubic inch size? Thanks.

 

There isn't even a debate here... the 350 is a better motor to build up, more cubes, more results for the same money spent. The difference between the 305 and 350 is in bore size, the 305 has a 3.74 inch bore, the 350 a 4.0 inch bore. The 350 can simply flow more air, with its larger cylinders. Also, few companies make aftermarket heads for the 305, and the stock ones flow like crap. Though the LB9 and the L69 are worthy motors, it doesn't make sense into sinking a lot of money into building one up, unless you are just doing it to have something different.

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91 Trans Am WS6
5.0 TPI auto
Flowmaster 3" 2 chamber catback
Trans Go shiftkit
2000 stall converter

supposed 'peanut cammed' car (yeah, right)

MoreMoodThatMod

 

MrJ summed this up perfectly. A 350 car with the same gearing and mods will beat a 305 car anyday. Plus, the 350 is probably easier to find parts for. TPIS and SLP mainly make parts for the L98, LS1, LT1 and LT4, all 350s.

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1987 Chevy Camaro IROC-Z
L98 TPI 350 (5.7L)
TH 700R-4 Transmission with 2.77:1 Rear End

Current Mods: Edelbrock TES 1 5/8" Headers, Hooker Aerochamber Cat-Back System, Performance Resource Chip with 160* Thermostat, Accel Ignition Components, K&N Filters, All Free Mods, Falken ZIEX Z-Rated Tires.

Best ET : 14.3 @ 97mph
(corrected for elevation)

 

Do we really need to answer this??? It will of course be the 350.

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TPI 305,
Gutted airboxes,
gutted MAF,
K&N filters,
Corvette Servo.
14.9@93mph

"Speed kills, wanna live forever, drive a Ford."