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Discussion Starter #1
:cheersSo, I'm buying a fresh 71 455 with edelbrock performer RPM heads with and 068 cam, never ran. The bottom end is a fresh rebuild with .030 stock pistons, so the seller says, but I believe him, friend. I'm assuming stock for 71 is 9.5 compression but I don't know the CC of the stock heads, so the E heads should up that. I don't know the head gasket width, but can fix that with some good advice.. Any experts out there with a guess on power? Should I upgrade the rods? Also, what is the best cam for a 2000 stall, cruiser/torque over the 068. I am considering a roller cam and new rods, but I won't really be beating on it, so this motor should live fine in my 70, the Jury. And give it street cred were the judge couldn't finish the deal, lol..
I have a turbo 350 with a shift kit, and a 3.36 open rear, posi coming next. I have a turbo 375 in the garage to bolt in, how much do I have to cut the driveshaft to bolt the long shaft Pontiac 400 in it?
 

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I can help with a little of this. Stock for '71 455 was 8.2 compression, done with 111cc and 114cc heads. The Edelbrock heads at 87cc will give you over 10:1 compression,which will be fine because they are aluminum......will need the same fuel that a 9-9.5:1 iron headed engine would need. No issues there. An 068 is pretty small for a 455....it would give you a lot of low end and run smoothly and well, though. Absolutely upgrade the rods....new forged are less than $300 a set, and cheap insurance. Others will chime in with more info, hopefully..............
 

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Depends on which heads they are - the round port E-heads come in two finished chamber sizes, 72cc and 87cc. I'd recommend either going a-head (ar ar ar) and pulling one of the heads to measure for sure, or checking for part numbers. I *think* mine have the part number stamped into the ends of the heads by the Edelbrock name, but don't remember for sure.

To really get an exact figure for compression you'll need to know the piston deck clearance anyway, and the heads have to come off to measure that.

Just "rough guessing it", 72 cc's with "usual" dimensions on everything would put you at 11.3:1 with 72cc heads, 9.9:1 with 87cc heads. (.040 gaskets, 4.18 gasket bore, .020 deck volume, 6cc's in the valve releifs)

I'd never recommend building a Pontiac that's ever going to see any 'spirited' driving without putting forged rods in it. Consider them relatively cheap insurance.

I love my solid roller cam, but they're on the pricey side so get ready - also if you go that route you'll want to put oiling restrictors in the lifter bores. Its not hard, I did mine myself, but you do have to thoroughly clean the block afterwards to make sure all the thread cuttings are removed.

How are you planning on driving it? --- Highway? Street? etc.

Bear
 

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Discussion Starter #4
They are performer RPM heads, it's stamped on the front of the head, so I assume these are them. Edelbrock 60599 Edelbrock Pontiac Performer RPM Heads
.575 max lift, so could be hard on a stock cam. 72 CC heads, so 11:1 compression, assume he did something to address this. I want to buy the motor, pull the pan and drop it in. But I know more, so I could put a couple grand more in and have a sweet motor. Funds being tight, throwing it in and upgrading later is a better idea. It has 10 10 crank and plastigauged. I'm doing it as a cruiser/show car, aluminum heads don't burn the paint off. It is an upgrade to a car that sits in the garage, it shouldn't ever see the strip, lol.. Dougs headers are in the future also.
What kind of torque/hp will the motor make as is?
 

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Discussion Starter #6
No, edelbrock performer intake, no carb. But seller has a couple 750 Demon double pumpers in the Corner I'm going to try to work in the deal. Stock rockers on it now, no nuts on them, just holding pushrods in. I need to talk to the builder to see why and what. Price is right, but need to ensure it was built to Pontiac specs.
 

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I think 11:1 CR will be marginal and probably too high for pump gas with aluminum heads. The 87cc head would be a much better choice for a street driven car on pump gas.
 

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FYI - both the 72cc and the 87cc heads wear the name "Edelbrock Performer RPM" - you have to use the actual part number (or measure) to be sure what you've got.

I agree that 11:1 is pretty risky for pump gas. You will find people doing it successfully by running the "right" cam ("big and rowdy" enough to manage cylinder pressure), but everything's got to be dead nuts on.

Bear
 

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The problem with big and rowdy cams bleeding off cylinder pressure at idle and low rpms, is that it makes up for the lost pressure in spades at mid range and full power. You can cheat a bit at light throttle and get away with it, but when you nail it, you pay the piper. Best to adjust CR to the fuel available, IMO. BTW, Bear, I for one appreciate your 'pocket protector' humor (a-head)!! LOL
 

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The problem with big and rowdy cams bleeding off cylinder pressure at idle and low rpms, is that it makes up for the lost pressure in spades at mid range and full power.
:agree 'Dat be true and is also another reason why Bear doesn't push the envelope. Right now the Beast is at 10.02:1 with aluminum heads. :D

In a conversation I had with Jim once I asked him about that very thing (high compression with a nasty cam), and he explained that the idea behind it all is that once the engine gets up into the power band and volumetric efficiency (VE) kicks in causing the pressure to jump, you're at an RPM where eveything is happening so fast that the motor tends to not have 'time' to get into detonation. Detonation is most likely at low rpm under heavy load, like going up a steep hill or pulling a trailer. That's the theory anyway and apparently some people apply it successfully, if they're being truthful.

Regardless, the point is that pushing compression ratio to the limit in a street engine is a risky proposition for at best a low to moderate benefit.

(Oh, and thanks for the kind words about my lame joke.. :D )

Bear
 

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Discussion Starter #11
I just searched it, the Performers are 87 CC, the RPMs are 72 CC. Hopefully he put dished pistons in it. I need to do more research, but am still stoked on getting the motor. So, what cam is the best for a street motor? Something that still pulls vacuum, and don't need a huge stall, but will "maximize" the combo?
 

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Discussion Starter #13
Here's the link from Edelbrock. The dif is the chamber size. Just read these heads are ram air 4 designed, so need new headers, not D port. How much are dougs headers, $800? Hopefully the PO already put the good rods in it..
Edelbrock.com - Cylinder Heads - Pontiac - Performer & Performer RPM
$1000 for a roller cam retro kit? May just go hydraulic and put ZDDP in, lol..
 

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As Mr. PBody is known to say, there are lots of ways to skin this cat. Yes, these are round port heads and take different headers. I'm running Doug's with 1-7/8" primaries on mine and they fit "reasonably well". I bought them in raw steel and used them that way to break in the motor on the dyno, then sent them out to JetHot in Arizona for their "extreme stainless" ceramic coating. Breaking in an engine will get the headers hot enough to ruin any coating, FYI...

If I had it to do over, I'd seriously consider MadDog headers. I hear they're very high quality and fit well.

Total header cost "the way I did it" was in the ballpark of what it would have cost me at the time to buy them coated from Dougs, and the coating I got is better than theirs. JetHot was a real pleasure to deal with too.

Ifn' it wuz me, I'd at least pull the heads and the pan just to be able to look everything over and take some measurements (like deck clearance, actual relief volume in the piston tops, etc.). Maybe even pull one piston so you can get a look at what they are, whether they're press-fit pins or Spirolocks, etc. It'd also be a good time to eyeball all the various oil gallery plugs and make sure they're all sealed well (especially the infamous hidden one in front of the distributor), make sure the lower dipstick tube and oil pump drive shaft are in place --- all the stuff that tends to cause forehead-slapping moments when they're discovered later after the engine's in the car. Also before you drop it in you'll want to double check the markings on the harmonic balancer and make sure it's not lying to you when it indicates TDC. Sometimes the're off a few degrees - mine was, and it was a brand new SFI-rated balancer. It's an easy problem to fix with a timing tape, but you have to know about it first.

Cam --- well, that's a personal choice based on lots of factors including how you're going to use the car, what rpm range it's going to "live" in, cost, rear-gear, transmission (and converter if it's an auto). After my experience, I'd never use a hydraulic roller (lifters are too heavy and all that mass is counterproductive to rpm) and although my first choice for me (obviously) was a solid roller I'd also consider a flat hydraulic or flat mechanical (in that order). First things first though.. I'd recommend you check the motor out first and find out for sure where it's going to be on compression because that might push you towards a cam to help guard against detonation problems.

Bear
 

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Discussion Starter #15
I'm thinking the same thing, tear it down and get a good look see at everything. I've been looking at the butler site for some ideas. Once I know what I have, I'm going to contact them for cam and maybe rods. I like there numbers and pump gas combos. Right now I'm trying to get my 66 decent enough to go to the body shop. Sanded all the PO's fiberglass work out of the floorpans, so I'm still itching today, rotten work. Also trying to rebuild the front windshield channel, it was swiss cheese. I want glass in it and in primer, then I'll let them do the remainder of the metal work and bondo. So, am preoccupied finishing that right now. I hate body work.
Just looked at mad dog, not many pics, but good looking stuff and priced right.
 

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Discussion Starter #16
Pulled the pan tonight, everything looks new, nice hone on the cylinders, new pistons, new oil pan and pump. Guess the builder was OCD, said PO had ton of money in the motor. It has 12 side bolts on the pan and intake, but I beam rods, N on the crank, 6 point rod bolts. Cam looks like an 068, stock hydraulic cam, not big roller, didn't pull the intake. I'm buying the motor tomorrow, what RPM range is this motor good for now. I can bolt it in with a new pan gasket, everything looks fantastic. Car is a cruiser, not going to be abused, lol.. $2500 with raIV E heads, Good? I'm trying to have him throw in a Demon carb, or cool finned valve covers. He's not budging. Had a check in my pocket for it. I'll buy new headers, they are the good heads. But, if I could run it as is for now that would be cool.
 

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sounds like a deal, just the RA E heads will set you back over 2K w/valves and such. should be fine with N crank and rods up to 4500 without any worries....hell mine barely sees over 3500 especially with the highway gear.
 

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Good at $2500? Yeah, I'd say so - you dog!!! :D :cheers

With a mild cam like that, you don't NEED to spin it. Your problem is going to be hooking it. That thing's going to make mountains of torque on the bottom.

Bear
 

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Discussion Starter #19 (Edited)
I got the motor, it's sweet! Can't wait to install it. Tried to post pics, but it gives me a fail message. Will try soon. Woo hoo, got my first aluminum head motor in my life!!
Anybody got a set of RAIV headers for break in. May get the mad dog headers Bear, then coat later. Do they fit better or as good as Dougs?


 

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Gorgeous! You -KNOW- it doesn't count until we hear/see video of it running, right? :cool

Just to be clear, I don't have first-hand experience with Mad Dog, it's just that I've heard good things and haven't heard any bad things.

I'm running Doug's myself (D-567's) and they fit "ok". Had to relocate the brake distribution block from the inside of the drivers side frame rail to the top of the frame rail, re-bend the back drive linkage to the trans, and turn the rear bolt on the passenger side lower control arm around so that the bolt head is on the 'inside' next to the header tube (and the header will have to be loosened when I eventually need to pull the control arm on that side to rebuild it).

Bear
 
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