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Old 04-26-2011, 07:44 AM
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cucumber1949 cucumber1949 is offline
T-Bucket, Corvette, Mustang
 
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Mild SBC top end upgrade

Looking to refresh the top-end of my SBC 350 in the T-Bucket. The 487 heads (1.94/1.50 valves) are showing signs of needing valve guides (sloppy) and I've already had each head off for a couple of leaking valves that were lapped in. Valves also show signs of leaking seals. I've been kicking the can down the road on these heads when it comes to fixing them properly because it looks like the money that it would take could be used to just about replace them with something better. I'll run these heads for the upcoming cruise season and then make the upgrade one of the winter projects. Bottom end is solid. While I'm at it, I'm thinking camshaft as well. This is a street T that has never seen the track and never will (won't pass tech).

Currently the engine is a Gen 1 3970010 block bored .030 originally out of a 71 El Camino. Flat top pistons with 4 d-shaped reliefs in the hole about .024" as I measured it the last time I had a head off. Currently using a steel shim head gasket and figure the SCR is about 8.5 or so with these open chamber 76 cc heads. Hydraulic flat tappet cam of unknown origin (could be stock). Currently running an Edel 1806 (650 cfm) on an RPM Air Gap manifold, 1 5/8" long tube roadster header into a 3" collector with tip mufflers. and an MSD 8360 distributor. Engine has an excellent smooth idle with good steady vacuum, great throttle response, accelerates very well (it's a T-Bucket LOL!), is a nice little cruiser and behaves well on the street. TH350 with a Hughes Performance flexplate and 2000 stall converter, 3.73 gears on 30" tires.

For the refresh, I�m thinking of upgrading to Vortec heads and a retrofit hyd roller cam that maintains the good idle and vacuum I currently have. Leaning towards some bottom end torque if possible. High RPM ops are not a consideration here, good street manners are important. I don't want to negatively change the personality of the car.

Here's what I'm thinking I'll use/need so far:

RHS cast iron Vortec heads , probably the 12407's (I see they're not available assembled in this small valve head)
Howards 110235-12 or 110315-10 with the Howards hyd roller lifters
New pushrods (around 7.144"? - will need the checking tool, hardened for use with guide plates)
New rockers - full roller rocker not important, maybe roller tip, stamped steel also okay with me
New valve covers and gaskets
New intake manifold (Air Gap style not important prob stay with an Edel, want to keep the 1806 carb though)
New timing chain/gear set
New timing chain cover, gasket and crank seal(will keep current short water pump)
Cam button
Possibly different distributor gear (will ask Howards for recommendation)
Intake gaskets
Head gaskets (will consult with RHS)
New head and intake bolts

It would appear the above setup will bump up the SCR to around 9.3 or so depending on the head gasket used. I'll have to see if I can work up an estimate of DCR but I don't think there will be any big surprises. My aim is to lean towards the low side on SCR but with the pistons .024 in the hole I'll want to keep an eye on quench.

Lift specs on these cams do not look like a problem with these heads. If I decide on the small valve heads I'd like to hear a recommendation for valve sets, springs, shims, retainers, locks, seals, guide plates, studs etc for use with a retrofit roller cam.

Any other recommendations on other parts is appreciated.
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