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What block?....now thoroughly confused. post #14

gone huntin

gone huntin

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As many know I recently turned my newly aquired Suburban into a submarine. It sat in floorboard deep water for two days. Water got into the engine and now there is a knock. I removed the pan and found the rod bearings were gone, but the mains looked great. While I was under there I decided to check my block numbers to affirm the 400 was indeed a 400 as it was supposed to be..............DAMNIT!!!!!!!! It's a freakin' 307!!!:doah: Well, it's not gonna stay in there! I have the 350 that came out of my '90 Suburban that needs a rebuild. What would be the best camshaft to use in that TBI engine if I'm gonna use an Edelbrock Performer intake and a Holley 600 carb. that are now on the imposter engine? I was thinking about an Edelbrock Performer camshaft, or maybe something with a little more bump. This is a trail only truck, hardly ever sees the road.
 
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If you are using the TBI heads I would not bother putting much cam in it. They dont flow much past 4500 RPM. Any good idle-5000 RPM low end cam is all you need. A good cheap cam that will work is a melling MTC1. You can usually get the cam,lifter set for around $120 or less.
 
Some people swap whatever they have in there sometimes . And since they all look the same , future owners never know . I really hate when they do that to people .

Happened to me too , except I was told my Chevelle had a 305 swapped into it , turned out to be a 1966 283 from a C10 , with one of my original 307 heads , and one head from a 72 Impala , that was funny as hell , two different chamber sizes and valve sizes :laugh: I at least only wanted it for the body , I have a .060 over block and the assembly parts new in packages .
 
Thanks for the response guys, I was beginning to wonder if anybody was gonna respond.
 
If it is a TBI roller cam block and you are going to use a carb instead, a good buy might be a used LT1/LT4 cam.
 
Thunder said:
A good cheap cam that will work is a melling MTC1. You can usually get the cam,lifter set for around $120 or less.
Click to expand...

I found the kit at Autozone for $86, but it says you must have an installed spring height of 1.75". Is this gonna work with stock springs?
 
comp or lunati 268. good power down low comes on strong @ about 1500 rpm. they spec roughly the same. 274 is about as high as you want to go with vac accesories. plus your supporting our local buisnesses with comp and lunati. just my.02
 
It's funny you mention that, I forgot that I know someone at Comp cam. I'm gonna call him this mornin'.
 
OK, I just got off of the phone with the guy I know at Comp cams, he suggested this cam, thoughts?
Part Number: CCA-12-321-4
Cam Style: Hydraulic flat tappet
Basic Operating RPM Range: 1,500-6,500
Intake Duration at 050 inch Lift: 224
Exhaust Duration at 050 inch Lift: 230
Duration at 050 inch Lift: 224 int./230 exh.
Advertised Intake Duration: 270
Advertised Exhaust Duration: 280
Advertised Duration: 270 int./280 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.470 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.460 in.
Valve Lift with Factory Rocker Arm Ratio: 0.470 int./0.460 exh. lift
Lobe Separation (degrees): 108
Intake Valve Lash: 0.000 in.
Exhaust Valve Lash: 0.000 in.
Computer Controlled Compatible: No
Grind Number: CS 270AH-8
He quoted me $183.21+ shipping for cam, lifters, timing chain, and break in lube.
I've also decided to use the heads off of the engine that's in the truck now. They are 33417369 cast heads 76cc 1.94/1.5 valves. They are 90-up 350 crate motor heads with perimeter vc bolts.
 
After giving myself a headache looking at the specs. on all of these cams I'm just gonna go with Thunder's suggestion on the Melling MTC-1. It's almost identical to the Edelbrock 2102 camshaft that matches my intake manifold an carb. It's also half the cost of both the other sets.
 
The cam you specd. from comp is about in the middle of the 268 & 274. would be interested in your impresions of the melling cam though.
 
I had a Comp 272H in my '87 after I did a head swap on it. Decent lope at idle, made some more power, but the TBI ran rich.
 
OK, I ran the block numbers (3970024) and it shows to be a 307, but the heads showed to be 90-up 350 crate motor heads (33417369) It also has a 350 crank in it(3932442). I figured somebody just didn't know any better, but I got the motor out today and tore into it. Everything looks brand new in it, it even has standard pistons. The bore looked a little big for a 307 so I broke out the mic and came up with 3.995". It's a 350? How? Surely they didn't bore a 307 out to a 350 did they? The crank is a 10/10 so it's not a completely new engine. There's no lip at the top of the cylinders so I may just hone it and put a crank in it.
 
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gone huntin said:
OK, I ran the block numbers (3970024) and it shows to be a 307, but the heads showed to be 90-up 350 crate motor heads (33417369) It also has a 350 crank in it(3932442). I figured somebody just didn't know any better, but I got the motor out today and tore into it. Everything looks brand new in it, it even has standard pistons. The bore looked a little big for a 307 so I broke out the mic and came up with 3.995". It's a 350? How? Surely they didn't bore a 307 out to a 350 did they? The crank is a 10/10 so it's not a completely new engine. There's no lip at the top of the cylinders so I may just hone it and put a crank in it.
Click to expand...

307 starts out a 3.875 bore . You measurement equipment could be off . I come up with 3.935 usiung the maximum bore of .060 over , which is usually the last rebuild of a blocks life unless it passes sonic check to go farther ( or its a rare blocked sleeved for a resto with matching numbers )

You got a 338 since they stroked your motor , not bad for a larger journal 283 block :thumb:
 
This is a 307 block bored out to a 350, it has STD stamped on the pistons. After I posted last night I did some online research and found that this is not unheard of. Rebuilders would do this if they were low on 350 blocks, or if they just had a 307 block period. The 350's were more popular than the 307's. The biggest problem was that you can't go any larger on the bore, standard 4.00 is all you can get out of it. I'm thinking that since it has GM crate motor heads on it, it might be a GM reman. The inside of the block is painted too. Either way it is a 350 now.
 
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