Lotsacubes

The L72’s sitting on a pallet waiting for me to decide where it goes. The block and crank will be refreshed, new forged SCAT rods and forged pistons. Not sure which brand piston yet, advise welcome. So the bottom end will be new, balanced, and top line. I’ve decided to go with a roller cam which led to suggestions about aluminum heads which allow 10.5-11 CR and 91 octane. The thot of seeing a pseudo L88 in there excites me in addition to the added hp fun. I know this may be blasphemous but all the original stuff can go back in if I want (kinda like the Muncie).

I intend to keep the original Holley but I guess it will have to be new between the carb and deck. I just have no experience to choose between AFR, Trick, or other al heads. Would some of you expert hot rod engine guys help a vette brother? At this moment in my life I’m drawn to the thrill of hp more than originality. Oh, not interested in having the original engine just setting around collecting dust and taking space. TIA

427Hotrod

As much as I love a 427, if I was buying a new crank, rods and pistons id make it a 489-496 for sure. It will pick up 75 hp and still rev like a chainsaw. Look stock and drive better than ever with the cubes.

Jim.

Lotsacubes

Jim, Glad to have your input. I was planning on reusing my stock forged crank. I envisioned rebuilding a really strong bottom end. Then project creep started from the deck up. A new forged crank is probably in the noise of this build. Seems SCAT rods and crank are preferred. Whose pistons do you like? I seem to recall you have Brodix heads.

GearheadJoe

I agree. If the goal is to have more power and you will be replacing the crank/rods/pistons anyway, there will be no additional cost to stroke the engine. Simply using a 454 rotating assembly will yield essentially "free HP."

I know these blocks can support even larger strokes than the 454, but I'm not sure what the threshold is where it starts getting more complicated to add stroke. Others here may be able to chime in on the issues that come up when you try to go beyond 454 CID

GearheadJoe

After re-reading your post, I see that you were planning to keep the original crank. That's not completely consistent with the goal of having a "top line" rotating assembly. Today's aftermarket forged cranks are made of much stronger alloys than what GM used for forged cranks in the 1960s.

427Hotrod

SCAT makes nice stuff. Wouldn't worry about it at all. Another choice is the Compstar line at Callies. It costs less than regular Callie's and is machined well. Howard's also has nice stuff. A set of forged pistons from 4032 material can be run at tighter clearances and makes nice street stuff. SRP, Probe, and several others for pistons. Mahle also makes some real nice kits with thin rings that work well. Just stay away from no name and off brand stuff like CAT ETC.

Ive got Brodix heads and always like them. Well made and heavy duty. AFR is another as welll as Dart. Used them all at different times. Just sort of depends on the whole combo. Each have advantages in certain builds.

How much power do you want? RPM? Trans and gearing?

Jim.

dmaxx3500

ive got 2 fresh [just dyno time] 588'' BBC complete from carb to oil pans

Lotsacubes

First Jim, I think my definition of adequate fun hp is quite different than yours. �� I was thinking 450-470 hp which with heads and roller cam seems easily attainable. Gears are 3.70’s with a TKO600 and Dual Friction. I want to use the original 3247 Holley which I think is 780 CFM? I don’t need 500+ hp, my wife and son drive it on rare occasions and it’s used in family weddings.

Thanks Joe, good point. I’m familiar with modern 4340. My goal is still to use the original block so it sounds like a new crank is cheap insurance. Seems like SCAT crank and rods are mentioned often and respected.

Of all the engines shops I’ve talked to or visited, Chad Golen has been the most helpful so far. He recommends AFR heads. It’s going to go to a shop that has a dyno. To get the engine back before Christmas I need to pick the engine shop in the next 1-2 weeks.

Nowhere Man

if your going to do this I would moth ball your original block and find a junk yard 454 and really play. so if something fails it wont matter

Lotsacubes

Yeah NM, I’ve considered that but I don’t thrash it that hard and just can’t imagine storing a big orange lump in my shop indefinitely. I understand your point, but I guess I don’t cherish it THAT much. I’ve never had this engine much above 5500 because I just don’t know what’s inside. After this build I will.

4 Speed Dave

When I built my BBC I went right to the 496 route, there is no reason not to. Who cares if you have a crank already buy a new one. I used Callies Compstar crank and rods with SRP pistons which yield 10.5-1 CR. Also if I may suggest to go hyd roller camshaft. Beware my crank and rod package did not clear the factory oil pan. I used a Moroso pan and an ATI balancer to round out the short block.

Nowhere Man

If your not going to thrash it why build it so you can? If that’s the case you can rebuild it bone stock and save a bunch of money and still have plenty of power to get you in trouble. If that is indeed the born with block it makes your car worth $$ over any other car. If your thrash it and put a hole in it you just lost more then a block.

GearheadJoe

Maybe the baseline implementation could be to build a 454 with a moderate hydraulic roller cam, and then plan to keep the rev limit under 6000 rpm. With a high quality rotating assembly, the risk to the original block should be low.

I find that for normal street driving (as opposed to drag racing), what really makes the car fun to drive is the torque generated between 2000 and 4000 rpm. For those rare occasions in street driving where I can run to redline, I don't want the engine to lay down until 6000 rpm, so I selected my cam accordingly. However, the truth is that it's hard to find safe locations where I can run to redline in anything but first gear.

I recently installed a 383 (424 HP on the dyno), with a TKO 600 and 3.70 rear. This combination is great to drive on the street, but it's hard to find a safe place to run it all-out. On the other hand, I love being able to simply punch the throttle at 2000 rpm and feel the extraordinary acceleration. Even with a rolling start and the clutch already engaged, I can light the tires in first gear with just the throttle.

With a 454, TKO 600, and 3.70 rear, you could probably do this in second and third gear as well. Unless you plan to drag race the car, this probably enough to keep a smile on your face.

cv67

454 blocks are plenty stout wouldnt worry about hurting it

427Hotrod

Yeah...I'm a little extreme....but your Hp goals are easy enough to get with the original 427 and iron oval port heads. You wouldn't even have to think to break 500 HP.

A mild 496 can make 600 HP easily...and with AFR heads will go 650-675 all day long. Stouter cam/intake carb will go 700+.

To make it easy for the wife to drive....just leads back to the added cubes. Cam it to peak around 5800-6000 or so and it will drive very easily. Use a dual plane intake and tune it and she'll like it.

For a quick reference...one version of my old 427 had 11.0 compression...but ran on 93 octane just fine. I had a set of iron Merlin oval ports that were nicely ported and used an ancient Comp 244* street roller cam. It peaked HP around 5850 RPM but would pull to 7000 RPM when I wanted it to. It drove VERY nice and was dead reliable. Ran low 11's@123mph launching very easily to save rear end parts. That was with a Doug Nash 5 speed and 3.36 rear gears.

Same combo with a 496 would be a street monster and even tamer!


JIM

Avispa

You can get 450 engine dyno HP from a 427 with original closed chamber square port heads, original intake and carb. Crane F-302 solid lifter flat tappet cam, 10.2 compression (Speed Pro L2300 forged version of 390 HP pistons). It would help get you there to put 1.88" exhaust valves in the heads and use the recommended valve springs. Runs perfectly on 93 octane pump gas. This setup will scorch the tires in 1st gear just mashing the throttle. M20 trans (converted an M21 by changing the main drive gear and counter gear) and 3.36 gears. Pulls strong right up to 6200 even with stock exhaust manifolds. How original do you want it to look?

For reasons I've never been able to figure out, the couple of hydraulic cams I've tried floated the valves at 5500. Hydraulic anything is off my list for big blocks for that reason alone. I know Jim has no concerns about solid street roller cams if you can plan to replace the lifters on a regular basis. No doubt a solid lifter street roller can would help, I'm just too lazy to change out lifters every do often.