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How do i tell the difference inbetween a 253 and 308 engine?:
There are several external differences inbetween the 253 and 308 engine,other than the internal differences ie..bore size,crankshaft counterweights etc etc. Visually it can be quite difficult to ascertain which is the 308 and which is the 253. The following details are provided so the user can denote quickly as to what motor they are looking at.(as most people will get abit shitty if you start to pull the engine apart in front of them!!)
1 Manifold- the first difference visually is manifold design, the 253 engine comes with a 2 barrell inlet manifold, with a WW stromberg carburettor, except for Commodores VC onwards and WB Holdens which have a rejetted 4bbl Quadrajet, The 308 engine comes with a 4 barrell inlet manifold and a rochester Quadrajet carburettor, however a common modification is to use a 308 manifold on a 253 engine. so further inspection is always a must.
2 Engine_Prefixes- This is the fool-proof method on checking whether or not you are looking at a 253 or 308 engine, this is assuming that they visually look the same. The Engine Prefixes are different.
3 Check the block- The "308 or "253" is cast into the engine block on the starter motor side of the engine(passenger side)you may have to get a little dirty and often it is extremley difficult to find the stamped "308" or "253" on the side of the engine block due to extractors, starter motor, engine wiring harnesses etc.