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Thanks Jebby. That's good. I just want to know that I have one more bore job before the block is trashed. Realistically, I hope I never need it, but I figure I should at least have one more overhaul. I did the same on the SBC 406 in my 77.
Given I have nothing yet, in terms of an engine, it seems to me I would be smarter to find a later model Gen VI block, with factory hydraulic roller capacity (cheaper), i.e. if going hydraulic roller, it is cheaper with factory setup than retro style. .....of course assuming I can get it at a reasonable price. From what I understand, the Gen VI does have mechanical fuel pump, and clutch attach bosses / holes. I see no downside in these blocks,......but welcome any input on that. And if I get a junk yard engine, I might end up with a good crank, parts and pieces? What do you say?
The factory hyd roller stuff is lift limited....I do not know what that number is but it is around .560 or so....at the rocker and .600 at the lifter....
Any Mark IV or Gen 5 block will work....but remember Gen 5 takes specific head gaskets to use Aftermarket Mark IV heads.....Also has specific bypass plugs for oil filter, a one piece seal that takes a different flywheel/flexplate.....and its own oil pan....
Consider this....my own 69’ 427/400 L68 was punched to 440, had a mild Comp cam in it and a real exhaust system....it was a beast.....BUT....if I could have added a half inch of stroke and more cam with headers it would have been an 11 second car even with oval port heads......
The bonus of getting a 454 truck engine is you can save big with the crank and rods if they are in good shape.....this is how you build a $3000 468.....
As Mark V-Pro said.....you can even make power with the peanut port heads.....they ARE 236cc’s BTW so why would it not work? The exhaust is pretty terrible on the truck heads so a LOT of short turn work is needed there.....
I sold my 82’ C20 468/TH400 longbed to my little bro a couple of years ago....peanut port, tiny cam, ZZ454 intake....headers, Edelbrock 750.....this truck will do 100 mph in the 1/4....with 3.73 gears.....
But another 80 horsepower is available from the large oval port if done right.....
The Big Block has as much folk lure and bullshit written about it as the small block.....I mean comical bullshit.....
Mark can tune you up on what to do.....he knows what he is doing. He will soon be an hour away so I will be glad to have a savvy engine guy in the area.
Jebby
Last edited by Jebbysan; Dec 10, 2020 at 12:13 PM.
454 blocks are more plentiful. They were around thru the 80s at least. Its only a casting code that makes it a 427 block, they have the same bore etc, Pretty sure can find you one for $300. The race shop has a few 454 steel cranks around for $300ish, Racers spending a few more for stroker cranks just leave them behind. A 2 bolt block is all you need for up to 600HP. Oval iron heads are around for $100. Low budget cubic inches. Add a 230ish cam and a decent build up and I'll bet you have 430-440HP and near 480TQ for $3-4k. It'll look original and run better than a stocker 390HP 427. But of course the numbers won't match. Any other route in parts selection will just cost you more $. Yes you can get more HP but I'm not sure that's what you want. You can get quite a bit without spending a lot.
Was gonna offer something similar....(2 bolt, ovals with some work and a simple 280 cam)
Cheap will run all day and smoke the tires off the rim.
like the ol 396/427 but with a stroke of a 383...why spend the $ and not get the bigger arm in there its all the difference in the world.
Was gonna offer something similar....(2 bolt, ovals with some work and a simple 280 cam)
Cheap will run all day and smoke the tires off the rim.
like the ol 396/427 but with a stroke of a 383...why spend the $ and not get the bigger arm in there its all the difference in the world.
Check out Chevy oval port heads, iron casting # 049 or 781. Bowl work, larger valves 2.19/1.88 (which gets you new seats ground) short side radius and port matching. You will not believe how these work on a 454 or 496! If you check around with local racers you can probably get a pair for under $500 ready to go. Tire shredding torque.
Last edited by Vette5311; Dec 13, 2020 at 12:29 PM.
Given I have nothing yet, in terms of an engine, it seems to me I would be smarter to find a later model Gen VI block, with factory hydraulic roller capacity (cheaper), i.e. if going hydraulic roller, it is cheaper with factory setup than retro style. .....of course assuming I can get it at a reasonable price. From what I understand, the Gen VI does have mechanical fuel pump, and clutch attach bosses / holes. I see no downside in these blocks,......but welcome any input on that. And if I get a junk yard engine, I might end up with a good crank, parts and pieces? What do you say?
The regular production Gen VI does not have a mech pump boss, and I do have one to know. The Gen VI Bowtie block does. Other than that they really are the best starting point.
Check out Chevy oval port heads, iron casting # 049 or 781. Bowl work, larger valves 2.19/1.88 (which gets you new seats ground) short side radius and port matching. You will not believe how these work on a 454 or 496! If you check around with local racers you can probably get a pair for under $500 ready to go. Tire shredding torque.
So,....OP here......say I do build a mildly built 454 for the 69 Convertible. WIth the Muncie M20 4 speed......think I should go 336 or 308 gears? I still want it to launch like everyone says a big block does.
3.36 min, still crusies on the hwy and less clutch slipping. That BB will have all the low end tq you need.
Vortecpro, friend has a nice set of 049s we took off his '31, nice shape. Are you looking? In So Cal
He wants to give them to me along with a 454 block but kinda want a 4 bolt....and probably go AFR or some ported 077s I have my eye on.
Compression, a healthy SFT cam basic st build.
So,....OP here......say I do build a mildly built 454 for the 69 Convertible. WIth the Muncie M20 4 speed......think I should go 336 or 308 gears? I still want it to launch like everyone says a big block does.
shoot for around 10:1 when you multiply 1st gear ratio times rear end ratio. A little less is ok with BB because of extra torque. Going farther off in either direction compromises the opposite end. Trade off clutch slipping for more top end or vice versa.
I just opened up the differential, and here are the pictures with codes and numbers. My quick decoding is this is a 336......which would be too good to be true. Still researching. What do you say?
Was surprised how good it looked inside comparted to the completely rusty outside......!
