Need input on 427 small block

[yellomalibu]

I must be missing something, looks like the one with the intake and carb is 500 less?

Some of those have cast internals, some have forged. Could it be that?

*edit* Nope, that's not it. Only difference I can tell by their description is 5.7 rods vs 6.0 rods... so different pistons, too. Different crank balance...

[Russell]

The one with 6" rods has a lower compression, and it looks like cam specs are different. So they are not the same. I guess the thing that threw me off wa the hp ratings are the same

[Scott Liggett]

H beam 6.0 rods with ARP caps screws, studded mains and heads with severe duty gaskets, etc

[BigAL]

Another thought is that even with the stock 3.75 stroke that a 400 has, if you run certain H-beam rods you'll have a problem with the big end of the rod hitting the cam lobes. I know I had it happen to me when I built my 406 and I was even running a small base circle cam.. I also had to grind the block at the oil pan rails to clear the cap screws on the rods. Saying that some manufacturers clearance the rods to clear the cam lobes for you, so shop around and do your homework and see which rod is going to fit best.

[MikeG]

Another thought is that even with the stock 3.75 stroke that a 400 has, if you run certain H-beam rods you'll have a problem with the big end of the rod hitting the cam lobes. I know I had it happen to me when I built my 406 and I was even running a small base circle cam.. I also had to grind the block at the oil pan rails to clear the cap screws on the rods. Saying that some manufacturers clearance the rods to clear the cam lobes for you, so shop around and do your homework and see which rod is going to fit best.

I appreciate you taking the time to make me aware of what to look for. I didn’t know that with a small base circle cam clearance would still be a concern, I’ll make sure that double checking the cam clearance is on my check list. Most of what I’m looking at are short block kits (assembled and unassembled) that do mention the clearance to the block was already done and now I’m hoping that they address the cam clearance issue by checking what they sell or by making some sort of recommendation on what to look at or buy.

[Scott Liggett]

Another thought is that even with the stock 3.75 stroke that a 400 has, if you run certain H-beam rods you'll have a problem with the big end of the rod hitting the cam lobes. I know I had it happen to me when I built my 406 and I was even running a small base circle cam.. I also had to grind the block at the oil pan rails to clear the cap screws on the rods. Saying that some manufacturers clearance the rods to clear the cam lobes for you, so shop around and do your homework and see which rod is going to fit best.

The rods on our 400's are clearance for this before balancing. The new block we designed is cast with the clearance at the oil pan rail for this stroke.

[BigAL]

I appreciate you taking the time to make me aware of what to look for. I didn’t know that with a small base circle cam clearance would still be a concern, I’ll make sure that double checking the cam clearance is on my check list. Most of what I’m looking at are short block kits (assembled and unassembled) that do mention the clearance to the block was already done and now I’m hoping that they address the cam clearance issue by checking what they sell or by making some sort of recommendation on what to look at or buy.

Being that you are looking at a kit, the rods will probably be clearanced or designed to clear the cam. Just make sure you have at least .050 clearance and you should be good.

[MikeG]

Well it looks like I need input again. I built this and ran into some bad luck. The mini blower self destructed after about 100 miles and it’s not repairable. So the input needed now is what to replace it with. I’m looking for belt driven boost. The motor is a 427 small block chevy using a Dart block, 6"” h beam rods, Wiseco pistons around 8.3 to 1 compression, AFR 220cc heads, mechanical roller with 575 lift, I may hit it with 50 - 200 shot of nitrous. I’m looking for opinions on the best (meaning durable) replacement, any type of belt driven unit (if I wanted a turbo I would have just went with an LS motor). Let me know what to do and why you would pick it for this setup. If you need more info on anything let me know

[yellomalibu]

I definitely learned something in this thread.

I never understood why blowers were under-driven or over-driven. Earlier in the thread, a concern was mentioned about the baby blower being over-driven, and now the concern has proven valid.

From the standpoint of someone who knows little about blowers, it seems now the wise choice would be to buy a big blower and have it under-driven. Apparently under driven blowers don't spin as fast and hence last longer on the street. They also look wicked cool on a street car!

[MikeG]

Just to clarify spinning this unit fast was not the cause of the issue (never got to that point). The unit was 32 year old and even thought I owned it since new, it was out of my sight for 10 year and after it broke taking it apart it looked as though the clearances were the issue. Spinning it by hand it looked good but spinning it a little faster, things were hitting. So my lesson, parts that have been sitting for so long (and not in sight) should have been looked at more carefully before I used them. This is not to say that at 140% overdriven would not have stretched the limits, but we will never find out.

[Barry Donovan]

there is a long wait state for the art of aluminum.
Taking air away with fire, and keeping carbon high (rich fuel)

Shame to lose a nice engine. You would not believe how far a subaru builder has to go (they do not admit much)

[MikeG]

I rediscover this post and thought I would give an update. I replaced the old broke B&M blower with a Blower Show 192, went EFI this year and add nitrous, the rest is the same as it was. Unfortunately I still have bad luck with this build and on the only start of a good pass to date the trans let go before the 1/8 and I broke a rocket then blew a head gasket, (no nitrous) and I still ran a 13.1. If I ever get my act together this thing should fly. Look for me at Drag Week 2019 if I don't break it before the event.