Ok— question about going from a 305 to a 350. I’m in the process of Building my hot rod. I have a 305 motor with a t56 trans now. I don’t know the condition of the 305 and have the opportunity to buy a 350. Can anyone tell me if the 350 will bold up to the t56 and if the motor mounts are like the 305? Just checking to see if it would be an easy swap! Thank you Sent from my iPhone using The H.A.M.B. mobile app
Only issues are the peripherals, due to changes around 1987-8. If both are earlier, then should be good, other wise could be different flywheels, and possibly no mechanical fuel pump, if needed.
Just be sure you have the correct timing case cover timing pointer for the dampener being used. EVERYTHING else is the same as far as bolting in, and bolting everything up; same flywheel/flexplate, starter motor, water pump, distributor, intake/exhaust manifolds-headers, all the tins and fasteners. I am Butch/56sedandelivery.
Some early 350 heads may not have all the bolt holes or pads for the holes for some accessories that the 305 might have but most mid 70 and later have them. If you don't have much more than an alternator it isn't a big issue. If you have power steering, AC and what not it might be.
305 and 350 SBC engines are externally balanced. After 1986 Chevrolet transitioned to 1pcRMS from earlier 2pcRMS. 400s were internally balanced. If it has a 2pcRMS the crank flange will be different with a counter weight. 1pcRMS crank flange has no counterweight and is wider.http://garage.grumpysperformance.com/index.php?threads/types-of-crankshaft-steel.204/ Check to see if your old flywheel will bolt to the new engine, if it does you're in business. As stated mounts are the same as is water pump, check your starter mounting location as well as intake bolt pattern, 4 bolts per side -v- 6 bolts per side. Is it a late model 350 (Vortec / centre bolt) or earlier 350 as 1st gen heads have shorter ports than later Vortec or LT heads so your intake may not fit? http://garage.grumpysperformance.com/index.php?threads/machining-vortec-heads-and-other-heads.401/ I've had a 305 in my car for 15yrs without issue. It came out of a wreck and all I did was change the oil, filter and plugs. The 305 is no world beater when compared to a 350 however it gets me from A to B and still fun to drive. Check it out first and see if you can get it to run before you jump in boots and all and keep the 350 as a spare? There is no substitute for cubic inches plus there are more performance options for a 350 than a 305.
^^^^^It's actually only the one piece rear main seal blocks/cranks that are "partially" externally balanced. The round crank flange negates the use of a balance pad, so it was added (a weight) to the flexplates/flywheels. The dampeners are still neutral balanced however. The 400 is the only SBC that used both a dampener AND flexplate/flywheel that were externally balanced engines. All 305, and most all 350 heads (only 1967 heads), had accessory holes. I am Butch/56sedandelivery.
Well, got the motor today and that’s my luck. They flywheels are different sizes and bolt patterns. What is the suggestions as to finding a flywheel and other components that will work? Sent from my iPhone using The H.A.M.B. mobile app
What size flywheel do you need? what other components do you need? telling us that might be a start, for folks to help you figure it out.
The size of the flywheel is 12 7/8” wide and came out of a 93-97 camero (t56). The 350 is 14 1/8” wide. The bolt pattern in center is 1/2 off. The biggest issue I see with some that I have looked at on McLeod website is that if the flywheel fits( it looks to thin form original), I think the hydrolic fork will not fit then. . Sent from my iPad using The H.A.M.B. mobile app
The later Vortec block (96 - 01) does not have the mechanical fuel pump mount machined. Need to use an electric. Same with the GM crate engines. The Old Goodwrench 195HP has the pump mount machined. The GM Performance engines with Vortec heads does not have the machined mount.
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