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Discussion Starter #1
Ever since I decided to take the Bird off the street and go racin I have been askin myself the same old question. "WHY" I dont have a racecar per say, all it is now is a striped out Bird. I tod my boy what we were going to do and boy did he jump on it. I came home the other day and he had removed the dash wiring and everything under the dash, including the turnsignal and headlight switch. There is nothing left but the dashpad and the instument panel. Now I have no way to go with it but forward.
Anyway
What I need is compression. I have the 4V open chamber 351C heads with a dished .030 piston. the heads and the block have been cut so I tink 9 to 1 is close. Maybe less, I am not going to change cams until I can afford new dome pistons.
Do ay of you guy's have a used set of .030 domes for a 351C?
Hell, it's late. I just had my last insulin shot for the day and I am just day dreamin of better weather when I can take it to the track and see what it will do. I have a goal of 12.99 to start the season but I would like to go at least 12.49 by seasons end.
Should I just go ahead and redo it now with the domes or just stay on course and play with it fow awhile? Most of you know my combo. I could realu use some input
Bob
 

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There will be a parade along in a few minutes to tell you that running domes in a open chamber Cleveland head is a recipe for disaster. Break down and buy a set of 4V closed chamber heads. You will pop the compression up and have little - if any - chance of detonation.

With dished pistons, you are not gonan get a huge increase in compression. My suggestion would be to get some flat-top pistons, get some closed chamber 4V heads, and get the cam you want. With the 4V head and flat-tops, you should get between 10.7:1 to 11.2:1 depending on what kind of pistons you get and how much you cut the block.

Find a guy named MonsterMach here on the forums. He built a killer 351C 4V and would have many helpful hints.

<font size=-1>[ This Message was edited by: CantedValve on 2/15/02 11:24am ]</font>
 

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I am all for the closed chambers and flat tops. That is a good move. It works much better than open heads with domes.
I would probably run it for a while so you can find out what you've got. Then you can upgrade with a little more education.
 

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Discussion Starter #4
Yea. I guess I would have to agree with the two of youz, when I first started this project I wanted low compression because it was to be a daily driver, and it did make an awsome street machine. But a friend gave me the open chamber heads as well as the 4 bolt block. I had ordered flat tops but got dished instead and figured I would run um anyway. I am on a four child income with a wife that refuses to work, so I cant just run out and buy heads. afterall I have damn near a grand in these and I didnt even have to buy them. It looks like I will stick with my combo for the summer and use it to tweek the chassis, then over next winter maybe build a 393 windsor and do dome seriuos racin next year. But for now I will keep my eyes open for a set of used .030 pop ups at a resonable deal and go from there
Bob
 

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Bob, are you running a Solid Cam? If so how big is it? I want to think that with a Hydro cam you dont have to have studs, and guideplates installed (but maybe with a BIG Hydro cam you do). Where are you from? I got my heads COMPLETE with studs, guideplates, valves minus the Roller Rockers from a man off Ebay. Price was 810. He has a shop do the machining for him. So getting another pair would be easy I would think. I am not sure if his prices went up any, but it is a starting point. My cam is similar specs to Larry's (Monstermach) but just a flat tappet solid. The cam and lifters was 256 I think. Heads 810. Sell your heads for 150 maybe, and your price would be in the neighborhood of 800 (If this mans price is the same) I was only about 60 miles so I saved on shipping and picked them up.

If you are gonna run the same cam, and it is a hydro, maybe you could get away with out the extra cost of milling the heads for studs, and guideplates?

I wish you luck!

PS, I got another Desk Top Dyno tonight...514 HP at 6500 RPMs and 462 @ 5000 RPMs The thing runs!!

Jeff Given
 

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just run it like it is......and add a lot of spray !! that's what that 9 to 1 motor will love.
 

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I don't know how much you had the heads milled originally, but you may look into having them milled more and/or tring to find thinner head gaskets, but you have to consider piston to valve clearence, pushrod length and intake fit. Ussally this is not a good idea with open chamber heads because of detenation (pinging) but since you're only going to race it, you could run it on racing gas. I'm in Illinois, I buy my gas from a small suppier who mainlly sells gas and diesel to farmers, but he carries turbo blue 112 for stockcar racers. Last year I bought a 55 gallon drum for $173 dollars, ALOT cheaper then buying at dragstrip!
Roger
 

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Unlike everyone else here who seem to think the open chamber heads are worthless, I have made good power with them and wouldnt "junk" them just to try and find some closed chamber heads. As a matter of fact, the heads on my race cleveland are open chambered 4v heads,(using closed chamber dome pistons) and the car has run as fast as [email protected] mph without any power adders.


I have run as high as 10.5-1 on the street with open heads using dome pistons without detonation. Camshaft selection is critical as is chamber preperation, dome preperation, and plug heat range. Of course, you cant run 87 octane in it.

The combo you have now with a good cam, and a good 8" convertor will run in the 12's without a problem.

Also, the heads you have now are worth closer to $300. If you dont beleive me, go look around online and see the price people are asking for 4v heads, open and closed. $300 is a "normal" asking price for open 4v heads that need valves and springs.
 

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Discussion Starter #9
I have some big bucks in these heads already. Ferrea 2.19 intakes and 1.7 exhaust valves, new bronze valve guild inserts, compitition three angle valve job, the valve pockets were opened up and ported by my local speed shop but the intake and exhaust ports were left alone. Also new Crane springs, retainers and keepers, I think if I come across some good used .030 domes I'll be happy.....Bob
 

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I don't think you will... you are gonna blow a hole in your piston at best.

Get some 4V castings and transfer your components after the required machine work is done. 4V quench heads will allow you to reuse ALL those components you just invested in... and you wont be melting pistons.

PS: If you are running dished pistons with open chamber heads, there is no way you are at 9.0:1. Try somewhere closer to 8.0:1

I think at this point you need to go with the juice. You seem unwilling and unable to go with the proper closed chamber heads you need to get your compression up without running racing gas.

kid - no, you would never be able to run 87 octane, and I gotta believe you were closer to 100 octane with open chambers and domed heads. Open chamber heads are just plain poorly designed for that high of compression... hence the reason they were never RUN with that much compression from the factory.

<font size=-1>[ This Message was edited by: CantedValve on 2/18/02 8:25am ]</font>
 

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When that motor was in my street car I ran 93 octane,without any octane boost. After 2 years of street driving and one season racing it, I tore it down and the bearings showed no signs of detonation nor did the pistons. I was running 36* of total timing and it ran fine. After having the head come of a valve and destroying a head, I rebuilt the motor using the same basic peices except I used closed chamber 4v heads. It only ran about .2 faster.

I also highly doubt it will burn a hole in a piston. Depending on how much the block has been cut and how much the heads have been shaved 9-1 is attainable with those pistons/head combo.

I still stand by my opinion that the open heads arent near as bad as everyone claims. My motor makes too much power without anything fancy inside for the heads to be "junk".
 

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Perhaps its possible... I would never try it though.

In the end, how much in machining work did you have to put into the heads to make them work properly?
 

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Typical head work. I pocket ported the intakes, fully ported the exhuast side, they were machined for screw-in studs, Ferrea valves, and they were shaved .050 to get the chamber volume down to 67 cc's. I also completely polished the chambers, eliminating every sharp edge, even the radius around the valve seat.

One thing that is kind of interesting though, the same port work yeilded 10 cfm less flow on my closed chamber heads (on the intakes).
 

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Discussion Starter #14
Make no doupt about it cantedvalve, I do agree with you on the need for closed chamber heads. But, the point is, I cant afford the things. It is intirely out of the question here with a six member family. I have four kids in school and I am the only income in the house. I also agree with the Kid, you can get good power out of the open chamber heads but like anything else in this bussiness you have to have everything right. The heads that I have are 4V heads and they were milled .030 as well as the 4 bolt block was decked .020, that was done because a sleeve was needed to repair the block when I built it. but let's not get into that. I do appriciate your input as well as respect your opinion Cantedvalve but as I said earlier I'll have to take my chances with what I have. Hell, If I would've known what was going to come about I would have built a Windsor to begin with but I had these laying around so that is what I have. Thanks, Let's keep up the comunication
Bob
 
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