These are rectangle port cylinder heads with open style 119cc combustion chambers and 320cc intake runners. In addition to the nearly 80lb weight savings these heads offer over factory cast iron heads, they will yield about a 40hp gain over stock GM 990 castings. In unported form these heads will support 500+ horsepower on pump gas. If you are looking for a race grade head that is comparable to Edelbrock, Dart, Trick Flow, Pro Comp P3021 same specs and flow numbers and AFR at a fraction of the price look no farther then these. These heads are machined and assembled by us. These heads work great on Carburetor and fuel injection engines, no special gaskets needed. The features of these are as follows. Heads are pressure cast from premium quality 2024 aluminum alloy. Unlike many inexpensive aftermarket heads that are sand cast these are cast in steel permanent type molds. This offers a stronger more durable cylinder head with consistent thickness throughout. 400 thick deck surfaces for maximum head gasket longevity. After machining the heads have magneese bronze valve guides installed along with stellite valve seats. This is the best available combonation for street use with unleaded gas. If you are racing the stellite valve seats offer much longer seat life then most competers ductile iron valve seats. Both the intake and the exhaust incoperate three angle valve seats to maximise both low and midium lift flow. The heads come fulley assembled with 2.25 stainless steel intake valves and 1.88 exhaust valves. These valves incoperate swril polished heads and undercut stems. In addition they have smaller 11/32 stems and are. 100 longer then stock GM valves. Valve springs are dual springs with a dampner on the head, they have 190-200lbs closed pressure and will accomadate. These will work fine with just about any hydraluic or solid flat tappett camshaft and roller cams. All the following parts work out of box with my heads! 142469376690 correct length 3/8 push rods. 142469376696 correct 3/8 guide plates. 232439450924 correct length 12 point cyclinder head bolts/stud kits. 142469379712 correct 1.7 ratio stainless steel full roller rockers with poly locks. 1.72 and 1.73 same. 200 longer rocker studs. These heads will accept all factory bracketery and accessories designed for 396-454. Standard headers and rectangle port intakes will fit fine. During this time we have had a great deal of feedback from our customers, these heads have proven to be street tough and race durable. The item “Chevrolet 396 427 454 496 502 540 BBC Aluminum Heads 320cc Rectangle port roller” is in sale since Monday, August 7, 2017. This item is in the category “eBay Motors\Parts & Accessories\Car & Truck Parts & Accessories\Engines & Engine Parts\Cylinder Heads”. The seller is “seperformance5″ and is located in Fresno, California. This item can be shipped worldwide.

• Manufacturer Part Number: 320 runner
• Part Brand: sce320
• Brand: sce
• Warranty: Yes