Advice needed on 427 block

[MrBuffet]

Hi all,

I'm basically a few days away from pulling the trigger on my roadster build, and I've reached the last decision point on my engine -- I have access to 2 427 blocks, and I need a bit of insight as to which one to pick...

Now regardless of which block I chose, there is a long list of parts which would be the same regardless of block choice, so let me just give a rundown of those;

- Original crank ground 10/10, magna fluxed, nitrated and cross drilled
- Original heads with factory adjustable rockers
- Original factory flywheel.
- Original Factory rods reconditioned with ARP bolts (De-beamed magna fluxed and nitrated)
- New "Original" cam (replica of mid-1960 ford race cam)
- New cam bearings
- New double roller chain
- New rod and main bearings
- New rings
- New gaskets
- New dampener
- New pushrods
- New Edelbrock intake manifold (Performer RPM)
- New lifters
- New springs

Now -- there are differences, and those are;

Contender 1 is a 1965 C6AE-C, 5J8 date stamp. It is cast as a side oiler, but drilled as a top oiler, it has been bored 0.020 over, however 2 of the cylinders have been sleeved -- the block has then been magna-fluxed and is in good shape. It is currently in short-block form, hence the piston choice was already made and it is Keith Black 11:1 flat pistons.

Contender 2 is a 1965 C5AE-A marine block, 5C12 date stamp, with less that 500 hours on it, no cracks. It is (obviously) cast as a top oiler, it has yet to be bored, and I could potentially get away with not boring it at all, but to clean it up really nicely would mean 0.020 over. the good news is that all cylinders are in great shape. It is currently in bare-block form, hence I can chose whatever pistons I prefer.

So here comes the big question -- which block to chose? --

- I'm hearing mixed views on trying to re-drill contender one to a side-oiler (especially because of the sleeving), any thoughts on that? has someone here actually tried to re-drill a top-oiler?
- I'm also hearing "buyer beware" on marine engines, as some say they were blocks that failed QA, and got deemed only useable for lower RPM duties. are some marine engines ok to use? what to look for?
- As this is supposed to be a everyday street driver, with no drag or strip (and I really do not want to deal with octane enhancer or race fuel) I'm hearing that 11:1 compression is pushing it for pump gas, and that 10:1 is pretty much the top with cast heads. Can someone confirm or deny this?
- In all reality what kind of extra value (outside bragging rights) would I get out of a side-oiler vs. a top-oiler?

Any advice / input would be greatly appreciated...

Thanks,

Peter

[cobrakiwi]

Block number 2 for me, as long as there was no trouble in the boat with it. As a street engine it will last and do all you need as a car engine.

[Fordzilla]

Block #2 gets my vote for your application. Yes, 11:1 will need octane booster. In my opinion 10.5:1 is the limit for pump gas. Anything over that- Plan on using octane booster or racing fuel.

[dcdoug]

I run 11:1 in my side oiler on 93 octane pump gas with no problems. Can't run less than 93 though, so depends on where you live. I bring octane booster for road trips in case I can't get good gas.

[MrBuffet]

Thanks for the replies guys -- much appriciated.

It sounds like the consensus so for is contender 2, and I would totally agree with you if it was not for posts elsewhere talking about the risks of corrosion/freeze-cracks in the water jackets for marine engines.

If I do go with the marine engine, I'm assuming the recommendation is to get it pressure tested as well as magnafluxed -- what kind of pressure is considered a pass?

Thanks,

Peter

[cobrakiwi]

If the water way's look good (No Scale) then get it pressure tested and a sonic test to put your mind to rest. You said it had no cracks so it should be fine.

[767Jockey]

With the 11:1 ratio, using aluminum heads helps. Also, maybe someone like Barry R. or Keith Craft, amomgst others, can massage the head chambers a bit to help bring that compression ratio down a bit? I know you said original heads, maybe the chambers can be worked on a bit on them too? I'm no expert by any means but it's certanly worth checking into.

[Argess]

To add to the consensus, I'd have used block #1, leave the oiling system as drilled, massage it a bit as per common pratice, EXCEPT that the sleeves worry me. So if you want another vote, go with #2. I assume both are cross-bolted, so no difference there.

Magna-fluxing and no cracks found? I doubt the need for pressure testing then. Even a cracked block can sometimes pass a pressure test. But added piece of mind is a great thing. I pressure tested a block once. Put a pice of plywood with sealer in as head gaskets, made up to aluminum fittings for oveer the water pump holes, filled it with water and then hooked the air compressor to it. Waited an hour at about 45 psi, 3 times the normal cap relief pressure, but one can go higher.

And "Lucky you!", having two blocks to choose from!

[MrBuffet]

Thanks again for the feedback -- much appriciated.

Not that I want to get into too much technicality here (ok -- I do!), how does sonic testing go to assure there is not rust/scale in the system? I get the pressure testing part, as that will show any rust penetration from the water cooling system to the outside (even minute stuff), but what does the added sonic test buy me?

Thanks,

Peter

[Argess]

Sonic testing is to check for cyl wall thickness. Normal max overbore for a 427 is 0.030". I think 427's were originally manufactured to have consistent cyl wall thickness, but other FEs were not done the same way. So a sonic test makes sure that the cylinder walls are thick enough to take the required overbore, especially in other FEs where core shift may have left cylinde walls thinner on one side than another..

EDIT: rust scale will be removed during hot tanking. Best to do your other tests after that.

[RICK LAKE]

MrBuffet Pete I see no problem with eithr motor at .020 over in the cylinder bores. If the Sleeves where installed right, the engine will last a life time and not leak or crack the block. You might be able to buy a set of .017" over pistons and get 2 rebuilds or more out of the block.
Crossdrilled cranks, You need to talk to one or all of these guys, Gessford Machine, Keith Craft Racing, or Barry R. at SurvivalMotor sports. The problem is a crossdrill crank uses about 20-30% more oil and kill pressure at idle. My understanding is that it's a race crank for high rpms and a poor street crank. If this is going to be a street motor with iron heads, 9.7 compression is safety max with out octane booster unless you have E-85 in your area. I was going to used a crossdrill crank in my 428 block and found that the oiling of the block would cause low pressure and volumne to the top end. Also a 100# spring and HVHP oil pump and a 6.5- 7 quart oil pan is a must.
Your rods are heavier than most for the street. I ran a set of eagle rods for 8 years of racing. ARP bolts in them, not the ones that came with them. No failures. Limiting the rpms to 6,000 and a max of 6,200 has alot to do with this.
There is alot more, I have to go to work. PLEASE do some home work before you deceide on what direction you go. There are some nice stroker kits out there with BBC rods that work. Running an iron motor will add about 100 pounds over and Aluminum motor with intake and heads. You can also go to a high compression with Aluminum heads. 10.5 is safe. Biuld a torque motor and don't worry about HP, It's a by product Rick L.

[Bobcat]

Hey Rick .... sending you a PM .

Bob

[elmariachi]

If I may ask, what are you estimating to have invested in thie marine-block-based engine when it is done and ready for the car?

Jim