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Old 07-16-2006, 08:55 PM   #1
Mr D.
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Default BBC Build Up Advice Needed

I picked up a complete STD bore 454 MKIV engine this weekend for my 65 project. The heads are P/N 14081045 and 14092360 (looks like this was a service replacement along the way). My goals are:

1. 400-425hp
2. Good sound through Factory Sidepipes
3. AC Car
4. Cruising around town, no racing or wild burn outs.

I will be using a 66 427 425hp Intake with Oval heads. Now I can either build as a 454 or 427, I would need to get a 427 rotating assy (there is one on ebay now. http://cgi.ebay.com/ebaymotors/ws/eB...MEWA%3AIT&rd=1

Looks like I will need a set of heads no matter which direction I head in.

What would you do with this engine? Cam? Pistions?

Thanks
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Old 07-18-2006, 12:12 PM   #2
427Hotrod
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Well this can go in many directions...all depends on how much you want to spend of course.

The first big decision is are you going to buy new aftermarket heads or use some sort of the stock oval ports? If you are buying aluminum heads, the sky is the limit.Price doesn't really change much once you go that way...just a lot more choices.

If I was going to lay out the money for a rotating assy with crank and rods anyway, I would for sure just go to a 489-496" deal with a 4.250 stroker crank. The cost is essentially the same. It's an easy build and will make incredible TQ while having better street manners than the 427/454 for what you describe.

You could use a very mild smooth cam and still make 550-600 hp pretty easily with good heads and that intake.


Even GM iron oval ports would make well over 500HP without even trying. Serious port work will go over 600 Hp with them too. Easier with aftermarkets ones though.

Don't ge me wrong..I love 427's...but they are best if you want to rev them pretty high. Your A/C and cruise mode deal will really like the big long stroke motor for instant fun when you mash the pedal.

JIM
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Old 07-18-2006, 02:29 PM   #3
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Jim

I think a 427 is the road I'm headed down if for no other reason I plan on putting 427 badges on the car so I would like it to have a 427 under the hood.

I picked up this engine over the weekend and it is a 1986 454 MK IV ($400) out of a 1 Ton Dulley that had 68K for miles. I have not pulled the pan but external view points to a 2-bolt block. It has an 8" timing cover. A 30 over bore is all this block will need and I plan on using the current rods with a new set of ARP bolts ($50).

Looks like I will need the following to short block it.

Machine shop - $400

Crank - $375 on Ebay

Piston Kit (piston, rings, bearings, pump, gaskets, ect) - Speed Pro L2300F30 pistons - $570

Oil Pan - GM P/N 14091356 w/ main studs $139

Timing Gear Set - $40

Blancer - $70

Cam & Lifters - $175 est.

Looks like $2200 give or take to short Block. I want to run Iron Ovals to keep the cost down and am looking for a set of closed chambered heads now.

So, the big question is what Cam to go with the L2300F30 pistons and Iron Ovals? I want a Hyd Flat Tappet and will be using a 66 427 435hp Rect Port Intake w/ stock manifolds and sidepipes.

I had a 427 with 063 heads built several years ago by a local machine shop that turned out great (strong running / loppy idle) but can't find any paperwork on what parts we used.

Given that I'm $2200 into the short block, add $500 for the intake, $100 valve covers, thats $2800 without heads. I would like to keep the whole long block cost in the $3000 - $3500 range.

This got longer that I expected but what are your thoughts on my plan so far?
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Old 07-23-2006, 09:34 PM   #4
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Well.....I have 427 emblems on my hood...and there is a 540 under there these days!!

You might even have a steel 454 crank in there since it came out of a truck. It's just a shame to give up TQ by destroking it, especially since your hyd flat tappet, stock mainfolds and restrictive sidepip[es aren't going to want to rev high. PLEASe at least put some different mufflers under the covers....because the stock stuff is so restrictive it will kill whatever motor you put in front of them.

Still like a 4.25 stroke for what you are doing...especially with a hyd flat tappet cam. Since you aren't going to rev it, might as well pick it up with cubes and no one wil know if you don't tell them.

But back to the 427 stuff...you might check Professional Products...they had a bunch of new steel 427 cranks a while back for $149. I know a guy who used one in a 4.500 bore motor and spins it to 8600 rpm regularly with no issues.

A set of the 049 iron open chamber ovals will flow very well with some port work done. You might even have them on the 454 already. If it were mine I would use them with L2268 type pistons to end up with around 10.0 compression. They are usually 118-120cc heads without touching them.

The other advantage of going to the higher performance version of the pistons is they have a larger valve pocket. The 2300's get real cozy with a 2.19 intake valve in the radius of the valvepocket. 2.06's do OK, but upgrading oval ports to 2.19's or 2.25's during rebuild is a good thing.

There are also some strange oval ports that were used on 454's that say "Hi Per" under valve covers...NOT "Hi PERF" as the rectangulars do. They have small valves and hardened ex seats, but they have large oval intake ports. Easy upgrade to install large intake valves in. You can leave the 1.72 ex valves and hard seats for what you are doing. Again, any of these heads will really come alive with a little cleanup work in the ports. If you can find a machine shop with a Serdi machine, you can easily install the larger valves.

Just do calculations on head work..it's real easy to get awful close to a set of aftermarket aluminum or iron heads that will outperform anything you're likely do get out of the GM castings without a lot of work. Check Brodix race rites and Dart. Dart and World products make some very nice ironheads....but again...aluminum isn't much more.

Or just use some GM heads off E-bay...but beware you don't buy junk.

Block machining...shoot for no more than .040 total clearance between head and pistons. If you don't deck block, you can use steel shim gaskets just like GM did to keep it tight. Aftermarket gaskets are usually .040 to .050+ thick and they will kill quench. Tight quench is critical to getting good performance out of stuff like this without detonation. This is an area many rebuild shops overlook because it's "easier" to ignore it.

Which oil pan is that? The GM true LS-7 pan is an excellent one and works well if you are going for the stock look.

Plain 'ole Cloyes 3 position $30 timing chain set is fine.

Not sure if your $400 machine shop bill will include balancing, decking boring, honing, feeze plugs, cam bearings, cleaning etc. Much less head work.

Cam choice we will need to work on after everything else is narrowed down. Again if it were me, I'd use a solid flat tappet.....less trouble and no pump up issues. They don't need anywhere the attention people like to act like if set up right.

Plus we can get better street manners out of a solid flat tappet than a hyd that will run as strong. Even the GM LS-6 cam makes a nice street cam. Comp makes an "improved" version of it that helps.

I wouldn't hesitate for a second to go up to .600 lift range, but you will need at least long slot rockers to do it. They can still be stamped type, but you can also get rollers under stock covers with two gaskets.

Since you are doing a 427/435 clone...I know many folks just bolt the square port intake on the ovals. but I couldn't do it without doing some severe port work to blend the big runners into the ports. Not too hard to do really. Too much of a mismatch otherwise.

I'm looking at an article from a recent Engine Master's book. They built a 427/425 for a Vette, then played with it.

First, using 2300 pistons and rect iron heads and the Comp version of the LS-6 cam, 427/425 intake and a 780 Holley and cast iron ex manifolds, they made 455HP@ 5900 rpm and 460 ft lbs@3900.

Then they added a Comp hyd roller 236/244 .521/.540 lift and some GM/Edelbrock rectangular ports along with a Victor Jr intake and 850 carb as well as headers. It made 508HP@ 5800 rpm and 480 ft lbs@ 4700. This combo "hung on" much longer.....as rpm climbed.

Next they slid in the Comp 288AR street solid roller cam and a set of AFR 305 cc heads. Otherwise all the same...made 596HP@ 6500 rpm and 520 ft lbs@ 5500 rpm. This "nasty" version made as much low end power as the 'stock" one did and was up over 150-175 hp at high rpm.

I can tell you the 288 street roller is a fantastic street cam. I ran it in my last version of my 427 with merlin oval ports.

Anyway, hopefully this gives you some ideas...as I said we can narrow down cam later.

But do the math.....get a stoker crank and pistons and rods for the same price as the 427 stuff almost. Use your 454 balancer.

Or save LOTS of money and use your crank, balancer, rods and just get the piston kit. Put the savings toward a better set of heads or cam setup. Gain cubes and power!!


JIM

Last edited by 427Hotrod; 07-23-2006 at 09:37 PM.
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Old 07-24-2006, 02:27 PM   #5
Mr D.
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Thanks for the input Jim

I got the heads off the engine and they are truck heads and the Balancer is bad (missing a small section of rubber). So, looks like I have the following to work with:

Std MK IV Block, 454 Crank, 11" Flywheel (454), Rods, Timing Cover and 069 Intake.

I'm ok with going 427 or 454 at this point as the deciding factor will be cost. The long pole in the tent right now is heads. The used stuff both open or closed chambered seem to be running $300-$400 for unknown condition or $750-$850 for freshly re-worked Ovals. That's a hard pill to get down considering the $300-$400 heads need that much in machine shop work and I can't see spending $750-$850 plus shipping on a used set of heads.



I ran the Comp Cam Nostalgia Plus N+LS6S Solid Flat Tappet in my last 427 and really liked this cam. It runs $447 in a K-Kit which will fill all my timing / valve train requirements. That leaves Heads and Pistons.

I need to locate a set of heads without breaking the bank.
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Old 07-24-2006, 09:13 PM   #6
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Time to do some searching with some Miami race dudes. There are bound to be some heads around here. I'm working in Miami this week...I can ask around..but I don't know many gear head dudes here.

I would hate to spend that much $$ on a set of stock rebuilt heads. it would just be sad.

Check "racingjunk.com" and the 'Chevelleforum.com" in the classified sections and see what you can find.

There are often deals on heads as folks "move up".

There are some very affordable aluminum ones coming in these days that seem to flow well. Again, the trick will be the manifolds and exhaust. I'll see if I can find a link to a guy who built a sleeper 496 with manifolds and iron intake and Q-jet. The flat intake hurt it more than anything, but it was a TQ monster.

JIM
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Old 07-24-2006, 09:13 PM
 
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