Locus2298
Newbie
Posts: 5
Reg: 09-12-23
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 09-12-23 01:27 PM - Post#2862502
Hey guys, I have an 86 MC, LS, with the original 305. Heads have 14014416 casting numbers, which if I have my info right, are 1.84int/1.50exh, with 58cc heads. I was planning to install the next parts on it, all from summit:
- Comp Cams K12-600-4 kit
Cam specs:
279int/297exh
At 0.50 227int/241exh lift
.479int/.465exh valve lift
- Holley 0-4777SAE 650CFM double pumper carb
- A forged rods kit, tbd
- KB KB144.030 piston kit - advertised to have 10.5:1 CR with the heads I have
- Weiand 7547-1 Single Plane Intake
My question is, does anybody has a similar setup? What HP and TQ numbers are you pulling with a similar setup? Will this even work? I would like a nice low-end torque with hard mid-torque. I have a TH350, 300HP kit on it, stock converter and stock rear end.
Any opinion will be greatly appreciated.
I already know that a 350 will be better, however, I'm from Costa Rica and getting hands on a good junkyard block here is close to impossible, even more impossible to get a full 350 or any other SBC, so I want to squeeze all power from the 305 I have. Thanks.
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 Shepherd
Valued Contributor
Posts: 3536
Loc: Lake George, NY
Reg: 11-11-15
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09-12-23 02:56 PM - Post#2862507
In response to Locus2298
10.5 is too much compression with steel heads. The cam and intake will hurt normal driveability unless you have more gear or a higher stall convertor.
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Locus2298
Newbie
Posts: 5
Reg: 09-12-23
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09-12-23 03:17 PM - Post#2862508
In response to Shepherd
I believe I have a 2000RPM Stall converter, per my time driving the car it starts moving on brakes at around 1800-1900 RPM.
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Shepherd
Valued Contributor
Posts: 3536
Loc: Lake George, NY
Reg: 11-11-15
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09-12-23 03:56 PM - Post#2862511
In response to Locus2298
My experience tells me that will not be enough with your planned mods. What rear gear ratio are you running?
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Locus2298
Newbie
Posts: 5
Reg: 09-12-23
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09-12-23 04:03 PM - Post#2862512
In response to Shepherd
Stock 7.5" 10-bolt GM
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Shepherd
Valued Contributor
Posts: 3536
Loc: Lake George, NY
Reg: 11-11-15
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09-12-23 04:36 PM - Post#2862513
In response to Locus2298
Ok, but what gear ratio?
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Locus2298
Newbie
Posts: 5
Reg: 09-12-23
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09-12-23 04:48 PM - Post#2862514
In response to Shepherd
3.73
Also,forget about that cam, I believe the XE256H will be a far better option. These are the specs:
256/268
0.447/0.454
RPM range from 1000 to 5500 rpm
I think that will give me the torque I want with the other components
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Shepherd
Valued Contributor
Posts: 3536
Loc: Lake George, NY
Reg: 11-11-15
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09-12-23 04:57 PM - Post#2862515
In response to Locus2298
Gear ratio will get the job done, but 65mph cruising will be around 3k, depending on tire size. Better cam choice. But compression is your next issue. My 305 with 60cc chambers and the block quench decked. .042 head gaskets, flat top .030 over pistons with 4 valve reliefs is right at 9.4 on paper.
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Locus2298
Newbie
Posts: 5
Reg: 09-12-23
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09-12-23 06:59 PM - Post#2862518
In response to Shepherd
I will install domed pistons, 0.30 OB. The head gasket will be an standard one. With the pistons I chose, I should get around 10.1:1 on paper. The pistons I will use are on the specs I posted.
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bobb
Super Senior Member
Posts: 6790
Loc: paradise
Reg: 09-05-03
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09-17-23 10:52 AM - Post#2862619
In response to Locus2298
make sure to get the correct quench. i would do a mild head port job. practice on a junk head to get experience. look at david vizard videos. stock rods will work fine. single plane is a mistake. send us some pasteles. lol
| 70 L camino, grampa engine, g-force 5 spd, road rage suspension. Pray first before all else fails. |
Edited by bobb on 09-17-23 10:57 AM. Reason for edit: No reason given.
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bobb
Super Senior Member
Posts: 6790
Loc: paradise
Reg: 09-05-03
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09-24-23 10:06 AM - Post#2862801
In response to Locus2298
another option if you have the desire and funds is a baby blower. it will add a ton of torque that would make it a blast to drive. downside is they tend to eat up tires. lol
| 70 L camino, grampa engine, g-force 5 spd, road rage suspension. Pray first before all else fails. |
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Bad56Sedan
"18th Year" Gold Supporting Member
Posts: 1863
Loc: Pasadena, Texas
Reg: 04-29-04
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10-05-23 10:34 PM - Post#2863126
In response to Locus2298
find this article
 Attachment: 001.jpg (999.7 KB) 301 View(s)
VC56S 2 door Sedan, 44 Years
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Bad56Sedan
"18th Year" Gold Supporting Member
Posts: 1863
Loc: Pasadena, Texas
Reg: 04-29-04
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08-31-24 01:24 PM - Post#2873292
In response to Bad56Sedan
wonder if the OP found the article?
wonder if the OP still has the car?
wonder if the OP trashed the 305 for a 350?
so many questions
VC56S 2 door Sedan, 44 Years
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