low compression

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IQ52 said:
Stroker,

You are right, 8.2:1 is low compression. But you can do respectable things with it as you well know.

My son bought his wife a 71 Scamp. He took the stock 318 bottom end, pulled some old 2.02/1.60 valves out of the trash can, installed them in the 318 heads with some bowl work, shoved a Comp 270S in the cam tunnel and used some 273 rocker arms and pushrods to hold the lifters down. Had a $20 aluminum single plane put under a $30 Edelbrock 600 cfm Performer. It sounds like a big block, makes 320 HP and turns heads where ever it goes. Pulls right off idle and feels like it will never quit winding. Uses 85 octane. Anyone can feel like they own a race even on 8.2:1.
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This is exactly the kinda build we're talkin about. That's why I went round and round with Bolig. He just never got it.
 
In terms of factory heads, the 906 "F" would be the best of the 906 genre. But none are real barnstormers without work. the intake ports on the 516 are flat but it's easy tog et them to move 260-270 which is more than enough for a street or mild race setup. If you throw them out, that's fine too. I wouldnt ask for them, but if I had a choice between building with them and using quench, or running open chambers, I'll run them in a heartbeat. The last set I used made 480hp on pump 91 with a hydraulic cam under .530 lift. It also made 530tq at 3200. They can be made to work, but in terms of hte best factory heads overall, I'll take the 346s for the intake SSR and the exh port.

As for what I'd use on a low compression deal, I would use the 516/915 combo. Because I can unshroud the valves, and not have the dead space by the gasket. Detonation will never be a problem. I'm looking to minimize the chamber size and the dead zone above the block edge. If it was a competition, I'd use a 413 for the stroke but the smaller bore. Of course, using that, i'd be stuck with the original pistons...lol.
 
Yeah, Richard Petty was big on the 346 heads. Honestly, I've never had my hot little hands on a set of 'em. I always thought if I could get a 906 intake with a 452 exhaust I would be in cylinder head heaven.
 
67 prostreet gt said:
go with what im doing, a 500 cube stroker, 440 block, indy heads, intake, quick fuel carb, should make around 570 with 10.75 to 1 compression, it all matters on the cam, used to know someone who always said, " cams make the engine, not the engine makes the cam" crazy i know but the man was a genius with a 413 max wedge
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With those heads and intake, I think you'll get more, a lot more. With that combination you could run a hydraulic flat tappet cam as small as 236/244 @ .050, .568"/.568" lift and get that power. We did 566 HP with Edelbrock RPM heads, Edelbrock RPM manifold, 10.3:1, and the hydraulic flat tappet.

Your motor is going to be a brute on pump gas.
 
The 346 was basically 71 only from what I know, and had cracking issues because it was the first induction hardening. But, they are the head you're talking about with the combo of as-cast ports... they have a better height than the 452s, but the better exh port. I have a set I started porting. The intakes flow 285 @.550, exh 181 @ .550, 2.14/1.81, and I haven't done much of anything with the guide boss on the intake side. I only got one head done. the other's only partial but it's a great casting if you can find them.
 
There are crate engines that can be bought for 5K......so I really don't consider that to be a budget minded price.

"MY" idea was this.....

Stock block, absolute, minimal, necessary machine work. ...and possibly machine work only liimited to cylinder heads....maybe with the exception of honing cylinders to remove glaze. New rings, bearings, oil pump, timing chain, camshaft and lifters.

Cylinder heads reconditioned only. Three angle valve job would be allowed, since that is a basic valve job to begin with. Valve springs to match camshaft (any flat tappet) but no upgrades such as porting or larger valves. No roller camshafts. Got a roller block? Use flat tappet lifters. Solid or hydrauilc, ok.

Some in the thread have scoffed at reringing without new pistons. I don't get that. In every single service manual, pistons have a go/no go specification, so what's the problem? The "you'd upgrade the piston if you tore the engine down" arguement doesn't hold water to me, simply because adding new rings and honing cylinders does bring back some lost sealing ability.

Also, I think any outside bolt on such as intake, headers carburetors ignition, etc., should be allowed. Just a basic "overhaul" as used to be known in the industry. It's even referred to as an "inframe" because the engine block is not removed from the frame of the vehicle. Not that I think it should go that far, because our engine bays are somewhat tighter than those of a large truck.

Some people seem to "shut down" when trying to lay some ground rules. There need to be some, so people will know what to follow. This would make the playing field level and the winner would be that who had chosen the best parts combo and assembled and tuned the best.

In that way, the difference between the winner and the runners up would be in the person, and nothing else. Wanna run ported heads? Fine, go enter another contest. Wanna run something other than a factory NON HP compression ratio, or something higher than an 8.5:1 blueprinted limit? Fine, go enter another contest. Nitrous? Fine, go enter another contest. Blower? You get it by now...I hope.

What I was thinking of was a bare bones overhaul that some kid in high school could afford. Something like what would have been our very first engine. But, what the hell do I know? Obviously not much, because nothing's ever materialized.
 
jamesdart said:
they are looking at 5,000 budget for the whole car not jsut an engine build. its kind of balls out, no exceptions, but they want real world values put on things, not things likt, i had all these stroker parts on my shelf to build an 11:1 451 and i had this old prostocker chassis so its all free. it all brands, fwd rwd nitrous turbo, whatever... just keep it under 5,000. guys are throwing out there plans, one guy is planning on doing a 2.2 turbo fwd, one guy a turbo 2.3 ranger, 455 pontiacs, amc... open to anything.
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It was my understanding that we were not talking about that here. Screw it then. Because I don't know what the hell we're talkin about anymore. Maybe I never did. That was time wasted for nuffin. Rob, now I know how you feel. lol
 
Can this include 318 too? I just found out that one of my head gaskets is leaking oil. So while I have the top end of my engine off I would do a few things. Most likely I will need to have the heads resurfaces but not rebuilt,clean the carbon off the top of the pistons,change intakes (Weiand Action Plus) and add a Eddy 1406 600 cfm carb.

I already have the intake and carb along with a adapter plate. So I might need a little help on the cam that will be best for my car. Here is some info on my car below.

car weight 4200 +/- a few lbs

Stock 318 was a 2 bbl lean burn now a 4 bbl electronic ignition

trans a A998

rear axle 8.25

gear ratio 3.08

27 inch tires may go to 28 in tires. (tire size is 255/60/15)
 
something about low compression... you get a slower burn which results in slower movement of the gases in and out of the chambers. Having bigger intake valves will give less power in the lower rev ranges with low compression because the outgoing charge can't scavenge as well. The trick is to get one of those Whiplash, Thumper type cams (or custom grind) made for it that build extra cylinder pressure and give good performance for low-compression engines.

EDIT: Heck I may propose the idea of a Hughes Whiplash 440 cam for my cousin's '72 Polara. Only 28,000 original miles on that baby and with a new ThermoQuad, Performer intake, HP exhaust manifolds and 2.5" TTI H-pipe system I think his engine could make good use of a cam upgrade. Anyone got specs on stock 440-4bbl. non-HP cams from 1972?
 
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i like hughes stuff, ive had good luck with it. im not sold on those whiplash cams though. they have a lot of overlap and the big selling point is the sound of them, they say it sounds like a funny car. i looked into one for my 400 in the duster. im not looking to have all bark and no bite, i cant see spending the cash on one to see if its really going to do what i want. i dont care if it sounds stock, as long as it makes the power where i need it.
 
http://www.hughesengines.com/TechArticles/dunnuckracing440withwhiplashhmc3245bl7cam.php
I know it may be biast as it is on hughes site and it is a 440...(I just picked up a 73 rv 440 block and am looking at options of building regarding the low compression 8.1-1 or so have found some tidbits here and there this one included. it can get pricey and out of hand fast once you start changing stuff in the bottom end..)

as far as 400's and 383's both are good, found the 400s stock compression kills them flat top pistons, but a ways down in the hole cast crank isn't a huge issue like a lot of people make them out to be specially if its a street car.... used a comp xe284 in both mills (383 around 9.5-1) and both would scream, hit 6500 regularly with both and 7000 few times accidentally with the 383. what killed both engines was not running headers off the 452 heads, but I was happy considering running through cast hp manifolds.. each to their own
 
rumblefish360 said:
No, not really. First, lack of parts description,second, is 10 - 1 plus really a low compresion ratio?

To ya both;
LOL, big deal, if ya know what I mean. I can build a 13 - 1 mill and run it on 87 as well. I'll just select the biggest cam in the book and retard the timing so it don't ping. But is 13-1 ratio really a low ratio. Is a 11.2-1 low?

I think, just IMO and thinking out louc here a second.....

I think the OP is on a wave length of what was stock. Not pump gas-able.
What would you both do with a near zelch ($0) budget and a low compresion 400 or 360? Stock pistons, no block milling no fancy crank off set grinding.

Design a set up to make power at a REAL low buck budget. Lets sweeten the mix with NO HEAD PORTING. Since this is a true low budget build. Assume the heads are dead stock, small valved and good to go. This takes rebuilding the heads out of the picture and as such, you can not squeezzzeee in commensts like,"Well, for only a few bucks more, you can back cut the valves."

WRONG, that's money spent that is not available. Come on now, the basics.

We'll accept headmilling.

Challenge on!

Now, who can not just type in thebuild, but actually do it and show it! I gotta '71 Duster w/a 400/727. It'll take awhile....the car is not in state.
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I dunno nuttin', but I'm learnin' quick around here, and I'm gonna give it a whirl. Put the engine in the cleaning tank last night.
 
Star there, man. See what you have first..
.Don't spend money,before you have to.....
 
440 block with a k1 technology stroker kit to 520 and some nice 906 heads and a Indy intake with a 950 four barrel and s nice set of headers with and electric water pump will make in the neighborhood of 530-550 hp

Posted via Topify using iPhone/iPad
 
think the op's have abandoned this thread....R U N N O F T....so we are all alone...and no one is home....
 
rbdart said:
think the op's have abandoned this thread....R U N N O F T....so we are all alone...and no one is home....
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There is a reason for that. I have a Motor home 440 that I plan to do under this low budget build. Very little new parts. Mostly cleaning and reconditioning of parts.
 
I am running a stock '81 318 bottom end in a '70 dart. Built it just for fun. Nothing fancy just a .450" [email protected] cam. I ported the hell out of the stock '81 heads with the stock valves. Performer 318/360 port matched with a big TQ off a '74 440. Stock electronic ignition and A-body 318 exhaust manifolds. The car is fun to drive, runs great on the cheap gas. Need to get it down to the track and get some timeslips before I install some cheap headers.
 
ibleedmoparts said:
The OP is home, but watching in the shadows
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Opies home..what are you doing watching in the shadows,make some rules make em stick and let er rip...we the peoples need some more motor ****,I think you had a great idea in the begining of this thread...i will participate...
 
IQ52 said:
The 516 is just not a performance head when compared to the 906. They may look the same to most people but there is a BIG difference. If you have a choice to go with the flow of a good set of 906s or the compression of the 516, "go with the flow" every time. Even the small chamber BB 915 can't flow as well as the 906 and I've tried real hard to figure out why.
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IQ, I like reading your replys and your #' are impressive. could it be that the open chamber nature of the 906 would naturally out flow the closed 915. thanks.
 
cryplydog said:
IQ, I like reading your replys and your #' are impressive. could it be that the open chamber nature of the 906 would naturally out flow the closed 915. thanks.
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Well, actually that does have a little to do with it, but the 915 chamber can be modified to compete with the 906 on the lower lift flows.

The struggle I was having was in the upper lifts. My son had to straighten me out on the reason for the difference in the higher lifts.

Even though the ports in the 906 and 915 look the same, they are not. There is a difference in the thickness of the casting in places. You can do more extensive grinding in the bowl of the 906 before you hit water than you can do in the 915, and there are other subtle differences.
 
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