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Old 11-12-2012, 03:09 PM
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Originally Posted by oldbogie View Post
The Vortec is not fully machined for a mechanical fuel pump, it can be finished off however. The Vortec timing cover is plastic and does not accept changes to the OEM timing gears and chain without some effort. They can be backdated to a metal timing cover. The question gets to the cam whether you want to keep it a roller or convert back to a flat tappet.

The cylinder walls don't extend as deeply into the crankcase as older 350's which simplifies putting a stroker crank in there but also reduces some support for the piston skirt, this pretty much demands a hypereutectic casting or a VMS-75/4032 high silicon forging in order to minimize the skirt clearance so high accelerations from wide clearances can't happen when the thrust sides change at BDC.

I'm not impressed by GM's powder metal rod, I certainly wouldn't use it for any high performance application.

It seems you have a pretty high stall converter is this because the 305 is running a big cam? A 350 running Vortec heads, Performer RPM intake, Holly of 650 to 750 CFM, a Comp XE 268 or any of the aftermarket equals to these can easily get to 370 hp and with some tuning, porting, 1.6 rockers, big tube headers and certainly a 750 cfm carb will go to 400 or so. Piston choice plays big on the low through middle high RPM power. A D-dish or flat top piston in-place of the OEM round dish piston for a common compression ratio of 9.5 to 1 and holding the squish/quench dimension to not more than .040 really wakes up the middle RPM ranges with as much as 20-30 foot pounds of torque and 10-20 horses. The round dish piston output converges on the D-dish or flat top at peak RPM but under that the better piston really carries the day with a fatter power curve. This curve also carries a slightly higher power peak at a bit higher RPM with a slower decay than seen with the round dish piston.

the reason why im running a high stall convertor is, at the time i was having my TH400 installed I wanted a wicked big block so that convertor was picked according to the engine by the trans company. years later, I've decided to just keep it a small block for driveability and price.
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