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Old 06-23-2018, 03:10 PM   #1
plowro8
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More HP from 305?

I am new to owning classic vehicles. I just bought a 72 c10 that has been partially restored. It has a smooth running 305 from an 84 Camaro in it, but it seems pretty low on power. Any suggestions on what can be done to gain HP? The other option, which I am not opposed to, is putting a new/newer fuel injected 350 in it. But, I don't even know where to start or who to talk to for advice and help on swapping a motor, since I am sure there a dozens of things to consider when doing so. Any suggestions on either option are greatly appreciated, thanks!

Ryan
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Old 06-23-2018, 03:35 PM   #2
rharris
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Re: More HP from 305?

I have heard using late 80's heads from a 305HO Iroc would be a noticeable help. I have a 307 that also does not have gobs of power. However, it is smooth, reliable, and fun to drive. I put a 600 edelbrock and HEI distributor on it and it made a noticeable difference. It's still a 307, just as your 305 will always be that. Unless, you are going into a lot of work and possible $ with the engine swap. Below is a link suggesting head swap. Maybe your 305 already has the HO heads.


http://67-72chevytrucks.com/vboard/s...d.php?t=739327
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Old 06-23-2018, 03:52 PM   #3
jessemthompson
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Re: More HP from 305?

305’s are not known for making big power. Swapping to a 350 would be more economical than trying to make a powerful 305. The swap is an R&R (remove and replace) job. No need to swap to fuel injection for the 350 either. Drop it in and enjoy. From that point on, if you want more power, the 350 reacts to power adders very well.
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Old 06-23-2018, 04:34 PM   #4
GASoline71
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Re: More HP from 305?

I know cats that have 305's hate to hear "just swap to a 350", but it is really the only way you're going to gain any HP and TQ. Now, you can have a good little engine with a 305 if you keep your expectations realistic.

Like said above, a 350 will fall into your engine bay where the 305 once was. For the most part externally a SBC is a SBC is a SBC... It's a very straightforward swap, as the motor mounts, transmission and the bracketry up front are interchangeable.

Gary
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I would never rebuild a 305.
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Old 06-23-2018, 05:06 PM   #5
rockyrivermark
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Re: More HP from 305?

If it runs as good as you say just enjoy it.
I wouldn't throw money at a 305. Enjoy the truck and if you really want more HP now or later down the line drop in a 350.
As you prob already know the 350 Mighty Mouse can pump out some serious HP.
Without breaking the bank.
I have stock 350 with just a few ads ons.
Only added
600 eddy carb $335 (old carb was a mess)
Performer eddy intake $175
HEI. $90
Headers and dual exhaust. $500
Actually more HP than I can stick to the pavement
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Old 06-23-2018, 08:11 PM   #6
indymachinist
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Re: More HP from 305?

Basically all the stuff that adds power to a 350 will on a 305 as well... the max number may be reduced but its still a sbc. Headers, good intake, carb, reasonable cam, etc.
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Old 06-23-2018, 08:45 PM   #7
Jz2518
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Re: More HP from 305?

Yup. Enjoy your 305. Its not meant to be a power house. Just cruise.
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Old 06-23-2018, 09:20 PM   #8
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Re: More HP from 305?

I had a 305 from an '85 Pontiac wagon that I junked, along with a 700 (4R) transmission which had been rebuilt not long before the junking. I rebuilt the engine with the smallest cam Edelbrock makes, along with an Edelbrock intake manifold, 600 CFM carb and cheapy headers. I dropped it in my '68 Skylark. I was using the small cam because I had plans to install a trailer hitch and tow a small trailer for camping (the small cam and overdrive trans were for mileage as well, since it was my commuter car). I never did put the hitch on. But that car would scamper right down the road with that setup. It had a peg leg 2.73 axle, and I had to go to 8" wide tires to keep it from burning rubber at take off. Not a real barn burner, but good enough. I got 17+ MPG in traffic (straight shot to work in the morning, 1.5-2 hours home in afternoon traffic on the 405 from Redondo Beach to the 118 fwy, then home to Simi).
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Old 06-23-2018, 09:24 PM   #9
rockyrivermark
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Re: More HP from 305?

I've had a few 305's. 4 total
I'll say they were all very reliable and the last one had
186,000 miles when I sold my '92 gmc.
Indymachinest makes a good point.
If you really want to put some components on the 305 for now they should all transfer over to a 350 if you ever decide to go that route later
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Old 06-23-2018, 09:58 PM   #10
plowro8
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Re: More HP from 305?

Thanks guys, I appreciate the feedback.
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Old 06-23-2018, 11:51 PM   #11
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Re: More HP from 305?

You could put money into a 305 or 350. Or you could swap to a iron ls for a little bit more money than putting some bolt ons on those gen 1’s and have a MUCH better starting point. Pretty easy to get 450 hp naturally from a lm7 5.3 and even more from an lq4 6.0. Easy and with a mostly reasonable price tag. As the saying goes “speed is money, how fast would you like to go?”
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