SBC discussion

[Recian]

Yeah I don't plan on high RPMs but I do like that low end power for hauling since that's what I bought the truck for to begin with. Now on the built 305 paul mentioned be worth it? I thought bout vortec heads, bored .030" roller valve train and since it shares the 350s crank and rods get a stroker kit from a 350. I know it's common sense smaller engine will get better MPG but would it even be worth sticking with a small bore 305 or just build a 350 the same way? What MPG difference could I expect between the 2? I do lke that my truck can get over 20 on the hwy even without the 700r4's O/D. Could I still get some more efficient 350 heads from the junkyard?

[INSIDIOUS '86]

Originally Posted by Recian

Yeah I don't plan on high RPMs but I do like that low end power for hauling since that's what I bought the truck for to begin with. Now on the built 305 paul mentioned be worth it? I thought bout vortec heads, bored .030" roller valve train and since it shares the 350s crank and rods get a stroker kit from a 350. I know it's common sense smaller engine will get better MPG but would it even be worth sticking with a small bore 305 or just build a 350 the same way? What MPG difference could I expect between the 2? I do lke that my truck can get over 20 on the hwy even without the 700r4's O/D. Could I still get some more efficient 350 heads from the junkyard?

A 305 would be ok for some light duty work. You don't have to do roller cams for power. Reason being that most rollers don't have any gain over flat tappet cams under 220/.050 duration. 305tpi with vortec heads and 700r4 won't be a slouch. Others will tell you it's a boat anchor but that's true if your drag racing only, 305 was built to do the work of a 350 but with less gas. You will have to do a vortec tpi base which will cost more money. You can do TBI swirl port heads with the stock tpi base which will be a lot less cost overall but TBI heads run like juggernauts till 3500rpm at which they become useless. Pick a cam that wil focus torque at the rpm you will be running at and it will do great. I would build the 305 or 350 the same way, the 305 should only be down maybe 25ft/hp at the peaks vs the 350.

A tpi 383 I would recommend vortec heads and nothing less to get the full benefit. That should be about 30ftlb/hp above the 350 with comparable setups, good if you really need the torque to tow.

Me personally if I was concerned about gas mileage and being able to tow normal truck loads a 305 and 350 won't be a whole bunch different other than having extra power if I need it, and when is that ever bad? It's not hard finding a low mile LB9 305 that just needs a quick refresh. You can get one with the tpi and you can swap the cam and throw in TBI heads for cheap.

There's a lot of things you can do, it all depends on what you want to do with the truck expectations and what you need it to do, of your hauling semis across the country maybe you need a big block?
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