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#1 |
Senior Member
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Location: Pottsgrove PA
Posts: 560
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305HO Heads on 307
I believe I read on here (or maybe on a chevelle forum) that mid 80's 305HO heads(14014416) would be a big improvement on a stock 307. It's time for a carb and I'm just trying to decide if I want to swap out the heads while I'm at it. I plan on keeping the ram horn manifolds. Exhaust is 2" dual currently. Any experience with the 305HO heads on a low-hp engine?
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72 Cheyenne Super C10 SWB 2001 Silverado 1500HD Crew 2011 Silverado 2500HD Crew Duramax (Hers) |
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#2 |
Registered User
Join Date: Jan 2003
Location: Safford,AZ
Posts: 3,612
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Re: 305HO Heads on 307
there are many benefits for the 305 head swap. Smaller chamber (58cc) hardened seats for unleaded, bigger valves (1.72 were stock 307, 1.84 for 305)
Me, personally, I would run the 416 castings on a 283 or a 307. |
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#3 |
Senior Member
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Location: Pottsgrove PA
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Re: 305HO Heads on 307
I was hoping to hear that. Thanks. I do not plan on changing the cam at this point. This is my first crack at engine work. I am mechanically inclined - I just want to start doing small things to see how they work and how much improvement it makes.
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72 Cheyenne Super C10 SWB 2001 Silverado 1500HD Crew 2011 Silverado 2500HD Crew Duramax (Hers) |
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#4 |
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Join Date: Mar 2013
Location: Campbellsville, KY
Posts: 888
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Re: 305HO Heads on 307
Probably better, with better gains, to up your compression ratio and valve sizes, etc. by doing 305 heads than putting a hotter cam, anyway. Chevy used the same calm cam in a lot of small blocks with substantially different horsepower outputs, getting more power by changing heads, pistons, carburetors, exhaust, etc. That is to say, the cam isn't the equivalent of a chip in a modern, computerized engine, that can open up tons more power for our truck engines with no other changes.
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Alex V. ------ 1967 C10 Suburban, 350/NP435, Green/Green, PS, PB, HD cooling, charging, shocks, and springs. 1985 GMC C3500 SRW, Sierra Classic, 454/TH400, white/blue. |
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#5 |
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Join Date: Jan 2003
Location: Safford,AZ
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Re: 305HO Heads on 307
Actually a Edelbrock 2102 or a summit cam k1102 combined with the 416 head really wake up the 307! You can even use a 80's aluminum intake with a late 70's quadrajet for a factory appearance.
Summit cam https://www.summitracing.com/parts/sum-k1102 |
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#6 |
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Join Date: Mar 2005
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Re: 305HO Heads on 307
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#7 |
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Join Date: Dec 2014
Location: Rockport, Texas
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Re: 305HO Heads on 307
Yeah, but here is the REAL question:
What shape is your 307 in?? Years ago I had a '68 C10 w/ a 307/powerglide. Probably the most gutless POS I've ever owned to this day. Actually ruined me on Chevy trucks for a decade. LOL. Anyway, the motor was tired and I came across a fresh rebuilt set of 305 heads. Figured the bump in compression would help the 307 out. Wrong. It bumped the compression alright... to the point that it blew the oil past the rings and the junk smoked like a freight train running down the road, burning oil like crazy. At that point, I was done. Parked it in front of the house and sold it. |
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#8 |
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Join Date: Oct 2012
Location: Green Valley Arizona
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Re: 305HO Heads on 307
Does the intake manifold have to be changed if you switch to the 305 heads?
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1970 C10 Short Stepper with 71/72 front clip. |
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#9 |
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Re: 305HO Heads on 307
Depends on which heads.
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#10 | |
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Re: 305HO Heads on 307
Quote:
081 or similar TBI heads, you can grind the center to get the manifold to fit vortec heads, yes you need to replace the intake manifold |
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#11 | |
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Location: Green Valley Arizona
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Re: 305HO Heads on 307
Quote:
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1970 C10 Short Stepper with 71/72 front clip. |
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