300 tempest upgrades?

Old 10-04-2019, 04:03 PM
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Default 300 tempest upgrades?

Whats everyones thoughts on building up a 300 tempest? They run a hotter cam than the 260's and correct me if I'm wrong but I believe they have a higher compression ratio too (9-1?). I've heard they have forged crank, forged rods, and forged pistons, anyone know if this is correct? If so this may be a nice candidate to upgrade due to the fully forged internals. How high of rpms can you safely spin this?
I think these were 300hp at the propshaft. Is it worth upgrading to roller cam and roller rockers? Maybe a call to Bob M. or just upgrading to a LT4 hot cam? How about a nice set of aluminum heads and intake too? With new heads and intake and cam, whats your thoughts on propshaft hp numbers?
Exhaust would be aluminum Gil small block manifolds with HP500 risers, the newer high rise type.
DjMikeyC is offline  
Old 10-04-2019, 04:46 PM
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Dont know about the tempest specs but you dont need any fancy parts to get sbc to 350-400 flywheel hp range. If the compression is 9.0:1 you are in the sweet spot imo. Stock heads with good valve job and bowl porting, comp xm or xe262 flat tappet cam, edelbrock rpm intake will get you there. I think tempest is rated at flywheel, not sure about that.
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Old 10-11-2019, 02:44 PM
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It was a cool motor but really nothing special other than the forged lower end.

The cam was around 214/224 @.44 valve lift. Much smaller than the lt4 hot cam. I would look at it like any other 350 you were going to build for performance. Solid bottom end, good heads, valvrtrain, induction, extaust, etc.
Mr Maine is offline  
Old 10-12-2019, 08:44 AM
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86 rating at the prop. Heads were the same as 260 so a better head would wake it up.

There is room for a better cam without reversion.
oconnor marine is offline  

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