Off topic 305 question
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From: Fresno, CA.
Off topic 305 question
Hello all,
Ok, I know a 305 is not a Ford engine but bear with me a minute please.
My neighbor who sold me my '76 F-250 bought a '69 GMC 1500 half ton pickup. It has a bad 350 motor and 3 on the tree manual trans. He purchased a 1989 Chevy 305 TBI motor with 5 speed manual trans to install in it, and he plans on using the Edelbrock Performer manifold from the 350 and a Holley carb on it. His son is telling him he has to replace the camshaft because it was designed for the TBI and will not run right with a carb.
I have not heard about that and wanted to ask. I admit I don't know too much about Chevies, but was hoping someone in this site might know if that is true or not.
Ok, I know a 305 is not a Ford engine but bear with me a minute please.
My neighbor who sold me my '76 F-250 bought a '69 GMC 1500 half ton pickup. It has a bad 350 motor and 3 on the tree manual trans. He purchased a 1989 Chevy 305 TBI motor with 5 speed manual trans to install in it, and he plans on using the Edelbrock Performer manifold from the 350 and a Holley carb on it. His son is telling him he has to replace the camshaft because it was designed for the TBI and will not run right with a carb.
I have not heard about that and wanted to ask. I admit I don't know too much about Chevies, but was hoping someone in this site might know if that is true or not.
Post Fiend
Joined: Jul 2005
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From: Durant, OK (SOSU)
A 305 in a half ton is going to suck. Badly...
I do believe the cams are different. It not running is another matter though. That thing is going to be lacking BIG time in the low end torque department, so a cam swap sure wouldn't hurt.
I do believe the cams are different. It not running is another matter though. That thing is going to be lacking BIG time in the low end torque department, so a cam swap sure wouldn't hurt.
Elder User
Joined: Sep 2006
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From: Alma Arkansas
It will run just fine on the stock camshaft. I've ran many engines with EFI cams on carburation and vise versa. But I would reccomend trying to keep the TBI setup. They're pretty simple and are lightyears ahead of any carberator. If you do go the carberator route you're going to need an older vacume/machanical advance distrubitor. Another hangup is a TBI engine with centerbolt valve covers has a slightly diffrent intake manifold from STD small block heads. An older style intake will work BUT you'll have to elongate some of the bolt holes with a drill. Also bear in mind that the 5 speed tranny uses a hydraulic clutch setup.
You'll get as much low end grunt with the stock cam as you're ever gonna get.
You'll get as much low end grunt with the stock cam as you're ever gonna get.
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From: Fresno, CA.
Thanks for the input Krochus.
That will save my neighbor money and time. He doesn't want TBI on his engine mainly because he doesn't know how to hook it up. (Neither do I) As for the distributor, the one on the '69 is an HEI with vacuum advance, so that should work for the 305. He is aware of the 5 speed's hydraulic clutch. I did not know about the difference in intake manifolds. He put the Performer on it earlier today and it looked like a perfect fit. Will have to take a closer look at the bolt holes tomorrow.
As for the 305 sucking in a half ton pickup, that may be true, however, the engine will have a Holley 4bbl on a Performer manifold and a set of headers so it should wake it up a little. I know it will not have the torque of the 350, but the owner is not looking for a race car, just a truck he can use as a daily driver.
I am not a big fan of the 305 motor either and tried to talk him into putting the money into fixing the 350. However, he has already bought the 305 now, and so we need to figure out how to make it work in his truck.
That will save my neighbor money and time. He doesn't want TBI on his engine mainly because he doesn't know how to hook it up. (Neither do I) As for the distributor, the one on the '69 is an HEI with vacuum advance, so that should work for the 305. He is aware of the 5 speed's hydraulic clutch. I did not know about the difference in intake manifolds. He put the Performer on it earlier today and it looked like a perfect fit. Will have to take a closer look at the bolt holes tomorrow.
As for the 305 sucking in a half ton pickup, that may be true, however, the engine will have a Holley 4bbl on a Performer manifold and a set of headers so it should wake it up a little. I know it will not have the torque of the 350, but the owner is not looking for a race car, just a truck he can use as a daily driver.
I am not a big fan of the 305 motor either and tried to talk him into putting the money into fixing the 350. However, he has already bought the 305 now, and so we need to figure out how to make it work in his truck.
Elder User
Joined: Sep 2006
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From: Alma Arkansas
As for the 305 sucking in a half ton pickup, that may be true, however, the engine will have a Holley 4bbl on a Performer manifold and a set of headers so it should wake it up a little. I know it will not have the torque of the 350, but the owner is not looking for a race car, just a truck he can use as a daily driver.
A 305 in a half ton is going to suck. Badly...
The issue with the intake is that the 4 center bolt holes go into the head at a slightly diffrent angle on a TBI engine. Nothin a drill bit taken to the intake won't rectify.
Last edited by Krochus; Dec 26, 2006 at 06:53 PM.
Senior User
Joined: Mar 2003
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From: Long Island
the 305 is not that bad. my dad bought a 3500 gmc 1 ton dually. 4 door, 8' bed. the previous owner blew it up and installed a 305 my dad thought it was a 350 when he bought it! it was carb'd and no emmission stuff. 3 spd auto with 4.10 or 4.11s. we used it to tow our 24' enclosed racecar trailer last season. a 3200 lb racecar plus all the stuff that goes with it and 4 or 5 200 lb guys. it would tow it alright. take a little while to get up to speed, but when you got there it would cruise at 65mph all day long. the only thing i would complain about is not enough power to pull onto a busy road towing that much weight. and that it sucks down the fuel.
the truck by itself could break the tires loose.
the truck by itself could break the tires loose.
Last edited by fast frank 66; Dec 26, 2006 at 08:06 PM.
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From: Fresno, CA.
That is good to know about the 305. 
And this 305 is a roller cammed Z/28 motor too. The guy he bought the engine and trans from rolled his 89 Z/28 and yanked the motor and trans before junking out the body. My nieghbor also got an aluminum radiator, headers, wheels, and t-tops from the guy all for $700. The only thing he will use though is the engine and trans. The radiator is too thin, and the wheels are 5 lug, and his are 6.
Will the mechanical fuel pump from the 350 work on the 305? It looks like it will with that block off plate removed, but does the cam have the eccentric to operate the pump?
And this 305 is a roller cammed Z/28 motor too. The guy he bought the engine and trans from rolled his 89 Z/28 and yanked the motor and trans before junking out the body. My nieghbor also got an aluminum radiator, headers, wheels, and t-tops from the guy all for $700. The only thing he will use though is the engine and trans. The radiator is too thin, and the wheels are 5 lug, and his are 6.Will the mechanical fuel pump from the 350 work on the 305? It looks like it will with that block off plate removed, but does the cam have the eccentric to operate the pump?
Last edited by Nighteyez; Dec 26, 2006 at 08:21 PM. Reason: add info
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Post Fiend
Joined: Jul 2005
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From: Durant, OK (SOSU)
Originally Posted by Krochus
not any more so than a 302
Both the 305 and 302 are lackluster truck engines. The mileage will be exceptionally low on a stock rebuild do the lack of low end and city driving, the 5 speed will keep the RPMs low (I doubt he'll think to keep them up), down out of the power range.
But hey, whatever floats his boat.
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From: Fresno, CA.
Well, since he drives like a grandpa anyway, I would be willing to bet he will not mind the lackluster performance of the 305. And if he does, he will just buy another project vehicle. He seems to do that anyway about every three or four months.
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Elder User
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From: Alma Arkansas
Originally Posted by Nighteyez
Will the mechanical fuel pump from the 350 work on the 305? It looks like it will with that block off plate removed, but does the cam have the eccentric to operate the pump? Or would we need to buy that?
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From: Malvern, Ohio
If hes gonna put a intake with 350 ports you might as well put 283 heads on it because they flow better, but you could just stick with 350 heads with the intake so you get good flow also so the 305 actually has power.
Id get flat top pistons for it because the highest compression the 305 ever had is 9 :1 and that was z28 and SS heads or you could just stay with stock dished ones with 1.85 intake/ 1.5 exhaust valves. Standard 305 heads have 1.72 intake valve diameter.
Id get flat top pistons for it because the highest compression the 305 ever had is 9 :1 and that was z28 and SS heads or you could just stay with stock dished ones with 1.85 intake/ 1.5 exhaust valves. Standard 305 heads have 1.72 intake valve diameter.
Last edited by 385seriesHemi; Dec 29, 2006 at 01:41 PM.
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From: North of Normal
Originally Posted by 385seriesHemi
If hes gonna put a intake with 350 ports you might as well put 283 heads on it because they flow better, but you could just stick with 350 heads with the intake so you get good flow also so the 305 actually has power.
Id get flat top pistons for it because the highest compression the 305 ever had is 9 :1 and that was z28 and SS heads or you could just stay with stock dished ones with 1.85 intake/ 1.5 exhaust valves. Standard 305 heads have 1.72 intake valve diameter.
Id get flat top pistons for it because the highest compression the 305 ever had is 9 :1 and that was z28 and SS heads or you could just stay with stock dished ones with 1.85 intake/ 1.5 exhaust valves. Standard 305 heads have 1.72 intake valve diameter.