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bought an 1970 chevy pickup!what should I do with it?

7K views 29 replies 9 participants last post by  454C10 
#1 ·
hey I just bought this truck for $800 and its preety clean Has a dent in the hood but the rest of it is straight,paints ok bronze and white.The engine is the only thing that doesnt look stock,It's an 85' 350 block,492 camel bump heads,has roller rockers 1.52 comp,an rpm intake and 1406 carb,plus an hei,headers and what looks like glasspack mufflers.The motor doesnt sound real big it sounds like it has a little more than stock in it,but the trans is a turbo-400,and it has a gm10 bolt with 4.10 gears in it.
The truck doesnt like this setup too much I think it needs lighter gears.I was thinking of swapping to a 3.42 gear and a th700r4 with a 2200 stall,but the motor im not sure yet I have a set of heads I bought from powerhouse a while back and they are 64cc/190cc intake runner 2.02/1.60 valves they advertise a flow rate of:
.100 64/61
.200 128/115
.300 181/158
.400 227/190
.500 260/209
.600 277/227
.700 280/231
I also have a set of 5140 full floater I-beam rods 6" with arp's.I also have a set of 40 series flows I think they are super 40's,I have a speed demon also in storage I bought a while back but never used it for my last project its a 650.
Im not sure I was thinking of building a 383,Im not interested being able to whip vipers or corvettes just want to whip all the other trucks on the road,lol.I want to keep a little mileage like 15-16 would'nt be bad on the highway.
I was thinking like maybe a 9.7:1cr 383 might do the trick,any suggestions on a combo?
 
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#2 ·
Pull off the glasspacks and install some dynomax super turbos. 2-1/4 or 2-1/2 exhaust will work fine with a cross over pipe before the mufflers. Glasspacks flow poorly and are loud as hell.

A 3.42 gear with a 700r is a good idea if you want some better mpg. 4.11's are hard to get good mpg with a non od transmission.

Sure a 383 would be better than a 350 but will cost money to build. If your 350 is in good shape then use it.

Trucks need low rpm torque so put on parts that are designed to do that.

A set of edelbrock performer heads (170cc) with a performer intake and a compcam 260H will move that truck nicely with a 3.42 or 3.55 gear. I would use a q-jet if MPG was a concern. Edlebrock heads come in three different combustion chamber sizes, so pick one that makes about 9.:1 to 9.5 with your 350.
 
#3 ·
Pull the th-400 and ship it to me. Then, pull the heads and ship them to me. You can have my 333882 heads. After that, freight the body and chasis over here, and you can have my '77. Its a beautiful specimen of chevy lace :D :D :D



Srry couldn't resist.

Honestly, ditto on what he said above. There's alot of good parts out there specifically for "RV and Towing" including cams. They are all designed for low end torque.
 
#9 ·
Im not worried about doing the 383 build at Powerhouse which is very close to my house they sell 383 kits almost as cheap as 350's.I wanted to get keith black pistons for 6" rods maybe 9.7:1,and a 5140 crank.Im not sure but I was thinking of running an Isky 270H mega cam 270 adv dur.,224dur.@.050,.500lift with 1.6 rockers,108LSA,104 intake centerline.
The old 350 had a 256H xe cam from what the last owner tells me.And it's mostly gearing that keeps it from doing as good as it can but the motor sounds to mild to me Im not as worried about mileage I really want this truck to perform well,and the motor got alot of miles on it.So I want to rebuild it bigger.Also the flowmasters are what I already have so im probably not changing them,they are 2.25" I have a summit x-pipe for it also.
This is the combo im thinking of:
383ci 9.7:1
TH700-R4 W/2200 stall
3.50 gear ford 9"
190cc powerhouse heads 2.02/1.60 valves
1.60 full roller rockers
270H Isky cam
Gear drive(pete jackson)
Performer rpm intake
650cfm speed demon carb
50K hei
headers 1 5/8"primaries 3"
2.25" x-pipe
Super 40 flows
 
#10 ·
454C10 said:
Pull off the glasspacks and install some dynomax super turbos. 2-1/4 or 2-1/2 exhaust will work fine with a cross over pipe before the mufflers. Glasspacks flow poorly and are loud as hell.

QUOTE]

If you choose the right glasspack it'll flow as much as straight pipe, the designs with a small core diameter are definately poor. A race type 3" or 3.5" glass pack will flow more than any street car will use.
 
#12 ·
Bad,
Yes, I know. The muffler site that I posted earlier had that result. The glass packs with the bumps in the ID flowed terrible. The good glass packs have a perforated tube in the ID (dyomax makes a good one).

Bonzi,
Sounds like a good combo. I would maybe run a little more gear, like a 3.73 but it still should run nice with a 3.50. It also depends on the size tire you plan on using. Also, the carb is a little small, and the compression could be a little higher with those heads. But again, not a big deal, should run good.

And as I always say, Use diesel engine oil with that cam.
 
#13 ·
with 411s you should have some real good low end torq, unless your running out of rpms b4 you get moving as fast as you want. if the 350 sbc is in fair shape, build a combo around the 350 platform/short block and use your 492s and get a cam for the rpms you want, just match the cam to the compression you have and the rpms you want. match your CR, cam, intake ect. and leave the 411s and put the 700R4 in it. or build a top end for the 350 and use your power house heads on the 350 with the 411s and 700R4. you can get some soild low end torq outa a 350. if the 350 isn't in very good shape or not what you want, build what you want like a 383 combo around the best set of heads you have and go with a 700R4 and 411s.

maybe you don't want the 411s even with the OD tranny I'm not sure.

if I was building a 383 I would build that combo in the rpm range I wanted and build it all around the 411s and use the 700R4. thats me.

http://www.bowtieoverdrives.com/catalog/catalog.php?Action=GETSUBCAT&CATID=B


Mustangsaly
 
#14 ·
the 350 in there now definately wants lighter gears the 4.11 makes 65mph @3700rpm it's a little high,it revs to 5000 easily in the 1rst 2 gears.
If I was to do more compression how much higher?These are cast iron heads from powerhouse,would I still be able to run premium?I wasnt sure but I thought Demon carbs ran more like 50cfm more than advertised?I think the tires are 295/55R17
www.enginekits.com(powerhouse's website)
 
#20 ·
Your planned engine combo sounds good except for the gear drive idea. Too noisy! Just get a good chain drive.

Leave in the 4.11's and install a limited slip center section. Then install a gear vendor OD on the th400 or install a 700R . If you install a 700r make sure to get the line pressures right with the TV cable or you will be building another transmission.

You will also need a 2000 to 2500 rpm stall with that 224 duration cam.

To speed up the process, just install the heads, cam, and intake on the 350 then upgrade the trans with an OD and higher stall.
 
#22 ·
It would be much cheaper to change the rear end ratio. However, performance will suffer. 4.11's will really help your truck off the line, especially if you install a LSD center section. A street engine needs gears to get a heavy truck rolling. And since you want it to be fast then I would stay with the 4.11's. Dropping to a 3.55 will feel like your engine lost 50 ftlbs of torque.

You can install a used Gear Vendor OD on your th400 for about the cost of a used 700r plus a rebuild. Should be able to find a used gear vendor with an th400 adapter hub for 1200 bucks on e-bay.

If I was building this truck, I would just drop in a 3.08 or 2.73 gear and build a high torque, low rpm, small block. However, I would not trying to beat every truck in the area. But if I were, then I would use 4.11's with an OD and an engine setup close to what you are planning to use.
 
#24 ·
A 4 speed is a different situation than a th400.

The shift points with a th400, 4.11 gear, and a 28 inch tire (typical truck tire) at 5500 rpms with be 45 mph (1st to 2nd shift), 74 mph (2nd to 3rd shift), 111 mph (3rd to Gear Vendor OD), for a 143mph top speed (5500 rpm) and a 2700 rpm drive at 70 mph. That tight gear ratio makes a fast truck.
 
#26 ·
gazim.

check out these ratios
http://www.chevymania.com/tech/trans-ratios.htm

Sounds like to me you need a wide ratio trans, like a M20, and a 3.23 gear. This will maintain a good gear ratio off the line then spread it out from there. A close ratio box is good for racing, not for street driving, especially with someone that doesn't like to short shift.

What are your engine spec's? (cam, compression, heads, carb, ect)

A close ratio M21 with a 4.11 will have gear ratios of (9.04, 6.74, 5.26, 4.11)
A wide ratio M20 with a 3.23 will have gear ratios of (8.27, 6.17, 4.78, 3.23)
 
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