Help me run on pump gas.

hotrod1956 wrote:It is a 1971 429 thunderjet. I want to keep it a 429. If I have to I will change heads. I have seen so many people say they run a 10.5.1 Comp engine and have know problems. So how is it done. I have read about 160 degree thermostat, timing at 10 no more than 32 all in, no vacuum leaks, carb can't be lean, cold air intake, 93 octane. May try the Singh grooves if some one can tell me it worked for them. Wonder if Edelbrock airgap intake would help. Thanks for listening.

rmcomprandy wrote:

hotrod1956 wrote:It is a 1971 429 thunderjet. I want to keep it a 429. If I have to I will change heads. I have seen so many people say they run a 10.5.1 Comp engine and have know problems. So how is it done. I have read about 160 degree thermostat, timing at 10 no more than 32 all in, no vacuum leaks, carb can't be lean, cold air intake, 93 octane. May try the Singh grooves if some one can tell me it worked for them. Wonder if Edelbrock airgap intake would help. Thanks for listening.

There are many ways to get it accomplished if you have no interest in making any power.
If you already know what you are gonna do and are not open to suggestions which don't agree with your own thinking ... then you are probably asking the wrong questions.

butterbean wrote:when you rebuild it the replacement head gaskets are .040 thick and that will lower the compression to about 10.25 to 1 and thats low enough for 93 pump gas and or you could also change the cam shaft to a custom grind that will allow it to bleed off some compression too, I would call and talk to one of the vendors on this site (like Randy or Scotty J) and ask about grinding you a cam for your application, hope this helps

69F100 wrote:What are you building a 429 or a 460 if you are building a 460 use the factory dish pistons with the dove heads you will be good with 92 octane.

DaveMcLain wrote:With a cam like the one in the original post the engine will be getting about another 20 degrees of duration at .050 vs the stock cam and this will make a tremendous difference in the low speed cylinder pressure and the ability to run on 93 octane.  I'm not sure about the intake closing event because I don't know what the intake centerline is on the stock cam but I'll bet even if you put this new cam in on a 106 that it'll still be later than the stock cam.

supervel45 wrote:https://www.429-460.com/t20940-d20e-police-heads?highlight=D20e+headers  I was thinking the same thing myself. He may have to check on headers though?

69F100 wrote:You could get a new set of dish piston to lower the c/r they may have to custom made might check. With  prob piston they may have a set or make you a set.

supervel45 wrote:http://www.wallaceracing.com/dynamic-cr.php   You can run your cam spec.s through here and see what the dymanic compression will be. You can also retard the cam to lower it. Like Randy said it will be a compromise with the high compression and low octane. I would use the D3 heads myself. You get to do away with the rail rockers and get hardened exhaust seats as a bonus. The compression ratio will be in the mid 9 range and with your cam at 0 or advanced slightly, and more ignition timing, should make more low end power, where you need it with a heavy car.

69F100 wrote:You could get a new set of dish piston to lower the c/r they may have to custom made might check. With  prob piston they may have a set or make you a set.

rmcomprandy wrote:Any "crutch" you use to simply be able to run pump gas would cost power.
Changing the heads to something like the D2OE-AB Police Interceptor heads would be the best thing to do, if you are set on keeping it a 429.

supervel45 wrote:https://www.fordmuscle.com/archives/2004/05/EdelbrockFlowTest/index.php   If you want to spend the money, the Edelbrock's are nice. They kind of copied the PI intake ports, and made the exhaust ports to fit regular headers, so that's a plus along with the weight savings. You will need roller rockers and hardened pushrods also.

supervel45 wrote:If you go with the Edelbrocks, you may also want to get their headbolt kit, as they are different than stock oem. Some people use the stock bolts, but it is harder to get a socket on them. Now you have to decide between the 75cc and the 95cc chambers, since they are aluminum and you can get by with more compression. If you don't like paying for super all the time, go with the 95's.