dejh22 Posted January 19, 2017 Share Posted January 19, 2017 Just picked up a 71 Monte from a member on here. It has a 454 create engine. The casting number is 12550313. Looked it up and this is what it says, 12550313...454.......91-up...4-bolt, Gen.V crate motor, Gen. VI 4.25" bare block, fuel pump boss It does have the fuel pump boss and 6 bolt timing chain cover. So that makes it a Gen 6. It has casting number 10114156 iron heads. It also has an iron intake. I think also it has non adjustable rockers on it. Someone told me it should be a roller cam. I don't think it is because when I pulled the Valve cover I could see down in the lifter valley and it looked to me like regular lifters. My question is it a roller cam? Has any one built a Gen 6 454 and what parts did you use? I want to lighten it up by using aluminum heads and intake. I figure if I go that far why not go all out with a roller cam. Only problem is I have very little knowledge with BBC's engines, let alone all the newer parts as in roller cams and such. Any advice would be greatly appreciated! Dale! Quote Link to comment Share on other sites More sharing options...
mrj52 Posted January 20, 2017 Share Posted January 20, 2017 Yep its a Gen 6 454 with the fuel pump boss. If it was a crate motor it would have a hyd roller camshaft, You would see the hyd roller lifter retainers, anti rotators and the "spider" to hold it all down. You also have peanut port heads which run fine but give up the power at about 4500 rpm. The stock camshaft that engine would have is a .483 lift intake and exhaust and 209 degrees at .050 115 lobe separation. Yes you can put a regular camshaft in this engine just use all the Mark4 early big block stuff. you can put the factory hyd roller camshaft in it using the Gen6 timing chain and cam retainer. Early Mark4 heads might not work on this block because the cooling passages are real close on the top row but all the aftermarket stuff bolts up with no problems. Ask as many questions as you want, Ill be 'staying tuned' TIM Quote Link to comment Share on other sites More sharing options...
dejh22 Posted January 20, 2017 Author Share Posted January 20, 2017 Thanks Tim. When I took the valve cover off I could see that it did not have retainers or spiders. The rockers are stamped steel with a bolt and not a nut. Unless I don't know what I'm looking at (which is very possible) it appears to me that it has "regular" lifters. I just went out and looked again. If it had retains would ther not be a bolt or screw to hold them in place? I do not see anything like that. I think what I would like to do is rebuild the top end as like the 454 H.O., but with aluminum heads. Dale Quote Link to comment Share on other sites More sharing options...
dejh22 Posted January 20, 2017 Author Share Posted January 20, 2017 Quote Link to comment Share on other sites More sharing options...
dejh22 Posted January 20, 2017 Author Share Posted January 20, 2017 After doing some online investigation. I find they made hydraulic roller lifters with no link bars. Maybe that is what is in this engine? I also found this write up Gen 6: GM recognized that it did not make any friends when it designed the Gen 5, and so they chose to revise the coolant passages again when designing the Gen 6, allowing the older heads to be used without coolant seepage problems. The boss for the clutch bracket returned, but was generally not drilled and tapped. The non-adjustable valvetrain remained, as did the one-piece rear main seal. Some but not all Gen 6 454 (and not 502) blocks regained a mechanical fuel pump provision. Production engines installed in pickup trucks got a high-efficiency cylinder head, still canted-valve, but with a modern heart-shaped combustion chamber of about 100cc. The intake port has a "ski jump" cast into it to promote swirling of the intake air flow. All production vehicles with a Gen 6 used a 454 version, but over-the-counter 502s are available. The Gen 6 is sometimes referred to as the "Gen Fix" because it fixed a number of issues that disappointed enthusiasts when the Gen 5 was released. As an added bonus, most if not all Gen 6 engines use hydraulic roller lifters. Quote Link to comment Share on other sites More sharing options...
mrj52 Posted January 21, 2017 Share Posted January 21, 2017 I am currently building several big blocks one of which is this 475 inch L29 GEN6 BB. Here is some pictures of the lifter retainers you see down your heads. These are the factory roller lifters and anti rotators. Quote Link to comment Share on other sites More sharing options...
dejh22 Posted January 21, 2017 Author Share Posted January 21, 2017 Thanks for posting the pixs. I really don't see any retainer or anti rotators. Mind you the hole I'm looking thru the head is small. I guess I just need to take the intake off and see what is in there. Quote Link to comment Share on other sites More sharing options...
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