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Opinions on daily driver 350 Engine Build
I have a 70 Stepside c10 that I just competed the install of new suspension and now looking to upgrade the engine. It’s a late 80s GM Goodwrench Target 350 which I have read is around 8.5 to 1 compression with the 76cc heads. I want to build a low end torque monster that can be driven daily so I am looking for opinions on my plan
Carb- replace 2 barrel with 600cfm edelbrock Intake- Edelbrock Performer Heads- Trickflow 175 DHC 60cc which should bump compression up to around 9.75 to 1 right? (like the original look of camel humps) Cam-Howard’s CL110225-2 with 1.5 rockers (I may bump up to the next size up the 235) For Rear gears I currently have a 12 bolt with 3.08 which I will upgrade to 3.73 when I replace the Turbo 350 with an overdrive Trans in the near future |
Re: Opinions on daily driver 350 Engine Build
Chevy converted to the one-piece rear main seal around 1986 and center bolt valve covers a year later.
Good start as hopefully your 350 likely has a one piece rear main and roller lifters. If your choice was the CL110225-12 not the CL110225-1? it has a 208 Intake Duration at 050 inch Lift. I consider that a good cam for your goals. I always pick a cam and then go one below. This procedure has worked excellent for me over the years. https://www.summitracing.com/newsand...ion-calculator Use this link for calculation the compression. I get some thing closer to 10.5:1. The aluminum heads will allow a higher compression without detonation. I am missing details like the piston dish and head gasket thickness so it's just a guess. The 3:73 are the real game changer. Most tend to underestimate the affects of a lower gear ratio. Personally I would complete the gear change before anything else. I can't remember for sure but the gear change may require a carrier change. If you have to change the carrier do a posi if you can. |
Re: Opinions on daily driver 350 Engine Build
The sucky part about the later 80’s Gen 2 small block stuff is that in the truck world most didn’t get the roller cam love until 96, and the crate engines seem to be largely hit and miss. The blocks have the lifter tray bosses but not all are drilled and tapped. Not that it’s a huge deal it’s pretty easy to add the roller setup it wasn’t originally equipped, just a little extra work to drill and tap the bosses and some extra parts.
If you’ve got a roller block I would definitely run the roller. Flat tappet cams are pretty risky these days. |
Re: Opinions on daily driver 350 Engine Build
'80s crate is likely 2-piece seal, flat tappet cam and 4-bolt mains. I'd dump that and get a later 1-piece core to build-maybe a '96-99 Vortec so you get those heads. Roller cam is the way to go. 2 bolt or 4 bolt makes no difference on a stockish engine. I like EFI but a carb is OK.
Bear in mind that a 700R4 has a very deep 1st gear so 3.08 may be fine for a rear ratio. I have a 700R4 in a car with 3.7 rear gears and first gear is useless. Wish I had left it 3.36. I would definitely try it before you change rear ends. My '83 K20 has 700R4 and 3.42 and it is a very good match IMHO. |
Re: Opinions on daily driver 350 Engine Build
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I don't have a 700r4 yet but i do want to upgrade the engine first to see how it drives and see if I even need to do the gear change later |
Re: Opinions on daily driver 350 Engine Build
The GM Targetmaster/Goodwrench engine has a very mild flat tappet cam, around 195/202, 112LSA, .383"/.401" valve lift. Seems like some had .390" intake lift.
Having installed a few of them over the years, I can say they have a smooth idle and make really good torque right out of the box. Dual exhaust or a set of headers with small primaries, along with a 600cfm or smaller 4-bbl will wake up the engine and fatten up the power curve. Been there done that at least 3 times. Actual compression as measured by magazines (and my math) is around 7.8:1. So your 60cc TF heads would bump compression up to around 9.0:1. You could also use a .028" head gasket for a little more. But I'd use whatever gaskets TF recommends. I had always looked at an Isky cam at 208/208 on a 108 LSA, but that was with stock heads and 7.8:1 compression. With 9.0:1 you could run a cam with 110 LSA for a less overlap and a wider power band. Guessing at head gasket thickness and how far "down the hole" the pistons are (varies from .025"-.030"), I'd say going from 75cc to 60cc chambers will get you more like 9.0:1. |
Re: Opinions on daily driver 350 Engine Build
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Re: Opinions on daily driver 350 Engine Build
IMHO a 700R4 with 3:08 would be a good combo. I had that setup (4L60E) and 3:08 in a SBC heavy car before I did a T56 swap. At most, do 3:42's with a 700R, especially with a tall tire. As mentioned 1st gear is very low so a 3:08 or 3:42 will be better, IMHO, than 3:73. Especially for Fwy driving.
A "RV" cam makes TQ down low and good for a street truck. |
Re: Opinions on daily driver 350 Engine Build
The other thing to consider with your build is a quality stall converter. I like and use Circle and Yank billet. Maybe 2500-2800 rpm stall?
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Re: Opinions on daily driver 350 Engine Build
hi, one magazine that did a big work up was Chevy high performance. they worked with the Goodwrench 350. the articles were called the Goodwrench quest. they were 7.8-8.0 to one stock. they ran a 4bbl headers and got 265hp and 350 ft lbs. not bad for a stockish crate engine. I bought one in 99 for my GMC. its been great. BROWN 70
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Re: Opinions on daily driver 350 Engine Build
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The OP here can google "Goodwrench 350 actual compression" and get lots of hits. |
Re: Opinions on daily driver 350 Engine Build
the Goodwrench quest is still on the net. good read I think there were 6-7 chapters. I put a 204 214 420 442 cam in mine with headers, hei, flowmasters with three cambers. its not overly loud. BROWN 70
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