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  #16 (permalink)  
Old 06-12-2012, 07:54 PM
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If you want more than stock power from this engine
you need to find better cylinder heads.
the 187 castings are the 305 TBI heads
with the swirl port. very restrictive at high valve lift and
over 4000rpm.
Find another small chamber head eg 305HO or L31 vortec

A 305 can make very good power but not with a low perf head.
The TBI head is intended for low rpm and fuel efficiency
but not power.

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  #17 (permalink)  
Old 06-13-2012, 07:36 AM
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This specific build is more about the actual build process then the hp at the end. I want to avoid buying anything where I can, so although the heads aren't great, I got them for free so I'll use 'em. I'm sad that it won't be a great engine, but let's be honest, it's a 305.
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  #18 (permalink)  
Old 06-13-2012, 08:03 AM
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Again the package makes the deal. Pull the trans back and put a higher stall in that supports the cam range. Use a 3.73+ gear in the rear. It will be a fantastic performer, that will take years of abuse. Even a 275 hp v8 will move forward well. You are getting a power stroke every 90 deg, and if you can keep making power to 5500+ rpm it will be impressive.

My recent experience with a kids camaro 350 /th350. Had a RPM/.454 cam k kit/ carb/ headers, but stock stall and rear gear. It was not that impressive. Had a 3000 stall been introduced and at least a 3.42 rear it would make all the difference. Relatively the same driveability retained.
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  #19 (permalink)  
Old 06-13-2012, 08:39 AM
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What is the engine going in?
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  #20 (permalink)  
Old 06-13-2012, 09:44 AM
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After my 74 Camaro is finished, I was planning on building a ratrod from scratch. This is tentatively its first engine, but I may end up replacing it down the road.
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  #21 (permalink)  
Old 06-13-2012, 02:06 PM
How fast is fast enough?
 
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Since you're missing a lot of stuff and need different heads I would look for a complete 305ho or vortec with little bore wear and rering it. It'll save you money, time, and aggrevation not to mention give you better results.
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Old 06-13-2012, 02:11 PM
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Quote:
Originally Posted by ap72
Since you're missing a lot of stuff and need different heads I would look for a complete 305ho or vortec with little bore wear and rering it. It'll save you money, time, and aggrevation not to mention give you better results.
Why does he need different heads?
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  #23 (permalink)  
Old 06-13-2012, 02:33 PM
How fast is fast enough?
 
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i didn't think he was going to stick with the swirl Ports.
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Old 06-13-2012, 02:47 PM
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He wants to build what he has not what he doesent have. Why would anyone spend a dime more than have to on a 305? The tuned port 305 is not a high rpm engine and they don't have swirl port heads. The highest factory HP rating on a 305 is on engine that does not have Vortec or HO heads. Why do you need over 4000 RPMs? Where are you going to drive it?
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  #25 (permalink)  
Old 06-13-2012, 02:53 PM
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  #26 (permalink)  
Old 06-13-2012, 04:41 PM
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The deal WAS to build what he has, so I agree- if there was going to be anything spent "unnecessarily" on the 305 (different heads, etc.), the only real choice that would make sense is to go w/a 5.7L L31 long block and be done w/it.

What I constantly see is "parts creep", where a poster asks about building a 305. And the next thing you know, everyone is arguing how to build the better 355 roller engine. I do this myself. If the guy wants to build the 305 then so be it.
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  #27 (permalink)  
Old 06-14-2012, 12:14 AM
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Fellas, fellas, let's not get distracted.

To clear up any confusion: My only serious purchases will be a new cam/lifters and pistons. These are the only things I do not yet have in my possession. For this specific build, free is better than performance. This will be on the street only.

I would like this thread to be about how to match up a cam and pistons to what I have. For example, someone mentioned 4-5 cc pistons. Why was this number chosen? How does one choose specific lift numbers for the cam to match the crank/etc.? (Do you even match cams to cranks? I sure don't know. You tell me!! )

I apologize if I confused anyone or agitate someone by building a "low-performance" 305.
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  #28 (permalink)  
Old 06-14-2012, 12:16 AM
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BTW, I've already learned plenty by reading the links you guys give and reading what you tell me. Thanks!
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  #29 (permalink)  
Old 06-14-2012, 10:04 AM
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Quote:
Originally Posted by Perkster029
Fellas, fellas, let's not get distracted.

To clear up any confusion: My only serious purchases will be a new cam/lifters and pistons. These are the only things I do not yet have in my possession. For this specific build, free is better than performance. This will be on the street only.

I would like this thread to be about how to match up a cam and pistons to what I have. For example, someone mentioned 4-5 cc pistons. Why was this number chosen? How does one choose specific lift numbers for the cam to match the crank/etc.? (Do you even match cams to cranks? I sure don't know. You tell me!! )

I apologize if I confused anyone or agitate someone by building a "low-performance" 305.


okay the reason i said that you need to stick with a 4-5cc flat top pistons is becuase you will want you compression ratio to be in the low to mid 9:1 area. the amount of recessed cc's in the top of the piston, a proper quench area of .040-.046", and the 64cc combustion chambers that the heads you already have play a direct role in what your compression ratio will be. since you can't really tighten up your quench are, then that leaves going with the a piston that has very little recess in the top as well as possibly seeing if milling the heads about .020-.030 is possible.

a 5cc flat top piston + .041" quench + 64cc combustion chamber heads = 9.2:1

a 5cc flat top piston = .041" quench + milling the heads .020" (est. 61cc) = 9.5:1

you mentioned why did i recomend a cam with a 210 duration @.050 and .430-.440". a factory cam in these motors would be around 190 @ .050 and .385". so the extra 20 in duration would keep the valve open longer and the extra .050" lift would open the valve farther alowing for more fuel/air to get into the cylinders. when you see a cam spec that says .430", that isn't at the lobe, that is at the valve, the cam compainy is already calculating the 1.5:1 rocker ratio into it. a .430" lift cam would have around .290" lift at the lobe.

as far as having your heads rebuilt, yes you could do it yourself, with the proper spring compression tools, it normally only cost about $80.00 (labor) to have a machine shop do it. your head will need the most amount of work, as it is the heads that are the biggest contributing factor behind making power. take the heads to a machine shop and find out what they need to be cleaned up, it may be that the valves are fine they just need knew locks and seals, have them check the springs as well and find out what they can handle lift wise.

here is a cam that would work well:
http://www.summitracing.com/parts/HRS-180315-10/
these lifters:
http://www.summitracing.com/parts/HRS-91113/
or you can probably just get a set of factory hyd roller lifters for less money and they would work just fine for what you are looking to do.

as i mentioned before, a performer rpm intake (i find it pointless to get the regular performer intake)
this carb would be great: http://www.ebay.com/itm/Holley-0-804...sories&vxp=mtr
this distributor would be great as well: http://www.skipwhiteperformance.com/...x?Item=6501-CL
(you dont have to get the one with the see-through cap)

you take all this, have the block machined, when rebuilding your heads you may likely have to have "Z-28" springs put on to accomidate a little extra lift, take a die grinder to the ports and just clean the casting up some and then smooth down the bowl/valve guide area (buy book, it will explain everything, SA design). with all of this, you should be looking at around 275hp/325tq. if would be a fun little budget project and would have some pep to it. i dont know what this going in but what ever it is i would suggest getting a shorter rear gear like a 3.73-4.10. this will make the vehicle much faster off the line. most "ricers" and even most mustangs wouldn't be able to keep up with you, but it wont be a barn burner.
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  #30 (permalink)  
Old 06-14-2012, 02:56 PM
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Thanks for that info. After an internet search and I think I've figured out compression ratios.

Based on my calculations, which I posted for everyone to spot any mistakes, I need an 8cc piston. (This is without milling the heads and assuming standard bore)

Also, how do you feel the following cam specs:

Duration @.050: 206 Intake/206 Exhaust
Valve Lift: 0.50" Intake/0.50" Exhaust
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