my 220 gpu conversion

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slidingforhogs
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Location: inverness fl

my 220 gpu conversion

Post by slidingforhogs »

Ok guys here's my delima, have a 220 that was fresh out of a gen , it has the 878 cam in it .. I put on a set of e225 cyls with pop up 4 ring pistons . before I changed it up i could only turn my prop 72/32 wood paddle nomore than 2500 . after the conversion it only gained 100 rpm . was found it want getting enuff intake air , so changed that and removed to holly 2 barrel carbon and replaced it with a 4 barrel carb, with only a minimal gain . again no great topend near the 3000 mk in seeking. Mg was also retired and set properly . starts right up . could there be a possibility that perhaps the exhaust could be choking it down? It has same headers that was on 220 cyls. Do they make a larger diameter tube headers ? If that could be the problem. Also replaced fuel pump putting 7psi to carb recommended. What else could be the culprit? I know its alto of questions but someone should know the possible fix.... Thanks mike
11'7 gore ,
220 gpu swinging a woody...

Stomp on it!!!!

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John Fenner
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Re: my 220 gpu conversion

Post by John Fenner »

Well, to be honest, you gained 100 rpm, but it should snap to that much harder than before, what size 4v did you put on it?
I never finish anyth,,,.

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kwanjangnihm
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Re: my 220 gpu conversion

Post by kwanjangnihm »

I have always read that a stock GPU cam was designed to NOT turn more than 2600 rpm.

Is the cam holding you back?? :scratch:
He'll cut your throat, baby, stick you in the back, drive off in your Cadillac.
He's more trouble than you think, he'll kill your sugar, leave you in the drink.

slidingforhogs
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Location: inverness fl

Re: my 220 gpu conversion

Post by slidingforhogs »

650 carbon , was told the 868 cam is the best cam for that engine , had others before and they turned it to 3k,
11'7 gore ,
220 gpu swinging a woody...

Stomp on it!!!!

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John Fenner
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Re: my 220 gpu conversion

Post by John Fenner »

650 cfm is a bit too big, what do you have the timing set at?
I never finish anyth,,,.

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John Fenner
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Re: my 220 gpu conversion

Post by John Fenner »

Also, do a wide open throttle pull, with very little to no idle time with engine hot, shut it off and pull top plugs, should be tan on insulator.
I never finish anyth,,,.

slidingforhogs
Southern Airboat Member
Posts: 105
Joined: Fri Oct 24, 2014 9:15 pm
Location: inverness fl

Re: my 220 gpu conversion

Post by slidingforhogs »

30dgree timing
11'7 gore ,
220 gpu swinging a woody...

Stomp on it!!!!

SWAMPHUNTER45
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Re: my 220 gpu conversion

Post by SWAMPHUNTER45 »

Was it WT Dave who was having a airboat cam and spring upgrade kit produced for the GP users ?

I recall something about that

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John Fenner
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Re: my 220 gpu conversion

Post by John Fenner »

30* is too high for the pop-up piston as well too high for dished pistons, set timing to 23*
I never finish anyth,,,.

slidingforhogs
Southern Airboat Member
Posts: 105
Joined: Fri Oct 24, 2014 9:15 pm
Location: inverness fl

Re: my 220 gpu conversion

Post by slidingforhogs »

Another question.. Has anyone cotton a wood prop and it not be the pitch that is stamped on it? Mine says 72lxl32g .. Its sensenich paddle.. I've had other 220s before stock that turned paddle props 3k with the same stamp before... :scratch:
11'7 gore ,
220 gpu swinging a woody...

Stomp on it!!!!

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John Fenner
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Posts: 2864
Joined: Tue Feb 14, 2012 12:26 pm
Location: Miami(Cuba) Fl.

Re: my 220 gpu conversion

Post by John Fenner »

I wouldn't recommend any paddle prop on any 220 Crank, a 2 blade Whirlwind stump puller is great on a gpu.
I never finish anyth,,,.

jeepinocala1111
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Re: my 220 gpu conversion

Post by jeepinocala1111 »

A holley 500 2 barrel is the carb you should be running a 4 barrel will not work as good.

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John Fenner
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Re: my 220 gpu conversion

Post by John Fenner »

jeepinocala1111 wrote:A holley 500 2 barrel is the carb you should be running a 4 barrel will not work as good.
Exactly, should have #75/6 jets, power valve plug off, and 22*/23* of timing.
I never finish anyth,,,.

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