Can i run pump gas

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Can i run pump gas

Post  litshoot on January 18th 2019, 11:44 am

I have old motorsports heads that have been cut down to 63 cc chambers 2.3 1.88 valves. Chambers show some ruff spots so im cleaning them up a little, maybe a cc or 2. putting them onto an existing bottom end build. the question comes down to do you think this motor with 11.2 roughly calculated compression will be ok on pump gas. NOTE MY MATH WAS WRONG ITS 11.8. NOT A SNOWBALLS CHANCE IM PUTTING PUMP IN. trick flow single plane, comp 34-803-9 cam, ross 8cc domes, .1875 headgasket 4.5 stroke.
Also for a spring package, What should I look for. do I need to run cups at the bottom to protect the aluminum?


Last edited by litshoot on January 18th 2019, 11:46 am; edited 2 times in total (Reason for editing : use the calculator backwards. im pretty much guaranteed that without quench and that ratio. shortly create a hole somewhere)

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Re: Can i run pump gas

Post  rmcomprandy on January 18th 2019, 12:03 pm

litshoot wrote:I have old motorsports heads that have been cut down to 63 cc chambers 2.3 1.88 valves. Chambers show some ruff spots so im cleaning them up a little, maybe a cc or 2. putting them onto an existing bottom end build. the question comes down to do you think this motor with 11.2 roughly calculated compression will be ok on pump gas. NOTE MY MATH WAS WRONG ITS 11.8. NOT A SNOWBALLS CHANCE IM PUTTING PUMP IN.  trick flow single plane, comp 34-803-9 cam, ross 8cc domes, .1875 headgasket 4.5 stroke.
Also for a spring package, What should I look for. do I need to run cups at the bottom to protect the aluminum?

You answered your own first question ... something steel has to be under the springs to protect the aluminum.

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Re: Can i run pump gas

Post  litshoot on January 18th 2019, 12:08 pm

In your opnion is 11.2 just as crazy. I wanted to be under 10.5 for pump gas.

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Re: Can i run pump gas

Post  BBFTorino on January 18th 2019, 3:26 pm

11.2 is not that crazy, some late model cars, like Camaro's have 11.5:1 and run on pump gas....of course they have knock sensors too!!
You just have to run the highest octane from the pump, and be a little conservative on your ignition timing.

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Re: Can i run pump gas

Post  rmcomprandy on January 18th 2019, 3:47 pm

litshoot wrote:In your opnion is 11.2 just as crazy. I wanted to be under 10.5 for pump gas.

With an 8cc dome ... your second figuring is closer.
A 542 with an 8cc DISH is over 14/1 compression with a 1018 gasket and a 63cc head.

With a .187", (48.8cc), thick head gasket and an 8cc DOME it is well over 11/1 compression ratio;
somewhere in the 11/7 range.
Successfully running pump gas at Wide Open Throttle with a lazy chamber having absolutely no quench at all, at anything over 125 degrees temperature is a pipe-dream.


Now you can begin your intake manifold fitment issues.

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Re: Can i run pump gas

Post  litshoot on January 18th 2019, 4:16 pm

rmcomprandy wrote:
litshoot wrote:In your opnion is 11.2 just as crazy. I wanted to be under 10.5 for pump gas.

With an 8cc dome ... you better figure it again.
A 542 with an 8cc DISH is over 14/1 compression with a 1018 gasket and a 63cc head.

With a .187", (48.8cc), thick head gasket and an 8cc DOME it is well over 11/1 compression ratio;
somewhere in the 11/7 range.

Now you can begin your intake manifold fitment issues.

Correct. the first calculation at 11.2 was with a 8 cc dish, the engine is 8cc dome pistons. .020 in the hole nets around 11.8 with the thick gasket. I used a different calculator as some use a negative for dish while others use a negative for a domed piston. it is domed. I have a .051 gasket, but that gets me near 17:1

As for the intake fitment issues im about to try. it came with an trickflow a460 manifold, im hoping went through the same treatments. otherwise how well do you feel an adapter plate similar to a price motorsports setup could be made to adapt a cobra jet manifold. may be better off seeing if a shop could skim down the intake. would it be the same thickness as the heads, and theres no way of knowing how much the heads have been shaved. back to square one. damn. This perfectly fits my unfocused build strategy. hooray

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Re: Can i run pump gas

Post  litshoot on January 18th 2019, 4:18 pm

A simple solution. Who makes a half inch thick headgasket.

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Re: Can i run pump gas

Post  pmrphil on January 18th 2019, 7:05 pm

Your local welding shop.

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Re: Can i run pump gas

Post  BOSS 429 on January 18th 2019, 11:49 pm

install a thicker head gasket
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Re: Can i run pump gas

Post  gordyd4 on February 3rd 2019, 1:37 pm

You could easily just run Torco to make up the needed octane.

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Re: Can i run pump gas

Post  rmcomprandy on February 3rd 2019, 1:51 pm

gordyd4 wrote:You could easily just run Torco to make up the needed octane.

WHY even attempt to go through all of this ? ... just get a different head.

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Re: Can i run pump gas

Post  wayney on February 3rd 2019, 8:16 pm

rmcomprandy wrote:
gordyd4 wrote:You could easily just run Torco to make up the needed octane.

WHY even attempt to go through all of this ? ... just get a different head.

what randy said. if you want to run an A460 head sell the ones you have and get new ones with the larger chamber.
my 572 Ahead motor at 11.2:1 runs on 93 pump gas . 9.8 in the quarter @ 3950lbs through 3in turbo mufflers and a C6 trans and we all know what power robbing transmissions they are Smile
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Re: Can i run pump gas

Post  litshoot on February 4th 2019, 10:12 am

Are a460 heads a little safer for running compression on pump gas. was timing cut back for that 11.2. im slowly resigning myself to the fact pistons are in my future, and closer than i hoped.

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Re: Can i run pump gas

Post  wayney on February 4th 2019, 6:52 pm

litshoot wrote:Are a460 heads a little safer for running compression on pump gas. was timing cut back for that 11.2. im slowly resigning myself to the fact pistons are in my future, and closer than i hoped.

I would have to check my log but if i remember correctly timing was at 31 degrees. any more and it slowed down and I didn't have a chance to try any less.

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Re: Can i run pump gas

Post  norm on February 4th 2019, 8:23 pm

They are all probably a little different but mine is 11:1 and run premium at 30 degrees, no issues but cam is fairly big so that helps.
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Re: Can i run pump gas

Post  biglucky on February 4th 2019, 9:32 pm

If you have E85 close to you give it a try.
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Re: Can i run pump gas

Post  litshoot on February 5th 2019, 9:51 am

e 85 is the new plan, but most of it is on hold, if I come across the heads, or sell some parts I may look to other avenues. I know of 1 e85 station. its 2 miles from my work, the problem is, Ive heard of others, but haven't verified it. online isn't very accurate for their locations. I disproved 3 supposed stations already

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