BUILD THREAD Street/Strip Cutlass Build: Race it, break it, fix it, repeat.

[Kwik_Cutty88]

Re: Budget Cutlass Build Thread, Making Progress.

Block stamping on the left rear of the block

Stamping under passenger side cylinder head

 

[BuWaGone]

Re: Budget Cutlass Build Thread, Making Progress.

A +.030 307 is 3.905 so with a 3.480 stroke 350 crank dropped in I guess that's really close to 350 cubes. 307 stroker! lol. Sounds more imprestive than the run of the mill 350.

edit* cubes actually come out to 333. Either way you have a cooler engine than your normal 350. lol

 

[Kwik_Cutty88]

Re: Budget Cutlass Build Thread, Making Progress.

I'll check the bore size one more time after work tonight just to be sure, hard to do it from the backsides with the heads on, but at least it's a close estimate. Also found original parts recipts from when we built the motor, these are the rings we got.

http://www.jegs.com/i/Sealed-Power/844/E377K/10002/-1

Correct me if I am wrong, but if the bore was any smaller than 4" then these rings wouldn't have worked right?

Also can anyone else verify these block numbers?

Stamping on the front decodes to either a 1970 307, a 1979 350, or a 1982 305 that was built at the Flint Plant in January. Date stamping next to the block stamping on the back of the motor says it was build January 16, 1971. And the stamping on the back of the block says it's a 1969-1973 307.

 

[Fox80]

Re: Budget Cutlass Build Thread, Making Progress.

I did some searching on this and it seems as tho your not the first one to find this combo, now if I understand this correctly it would take a special piston to make this correct, all SBC use the same rod except the 400, if this is a mismatched motor I would wonder how it was balanced, a 350 crank is balanced at the factory for the larger bore/stroke 350 piston, I have a bad feeling about this combo, if this were my motor I would have the rotating assembly balanced. I know your tight on funds but this stuff is not adding up right, I never trust a previous owner so I would pull it apart and get it looked at. Do a google search for the casting number at the back of the block you will find some good articles

 

[olds307 and 403]

Re: Budget Cutlass Build Thread, Making Progress.

Can you go .100" overbore on a sbc? I know pre 76 Olds 350's can go that and maybe more. I thought most sbc can go .060" max, correct?

 

[Fox80]

Re: Budget Cutlass Build Thread, Making Progress.

There is not a block I know of that can go that big, aftermarket blocks can, but even .040 is not advised on a 400 block because if the thin cylinders

 

[Kwik_Cutty88]

Re: Budget Cutlass Build Thread, Making Progress.

I did some searching on this and it seems as tho your not the first one to find this combo, now if I understand this correctly it would take a special piston to make this correct, all SBC use the same rod except the 400, if this is a mismatched motor I would wonder how it was balanced, a 350 crank is balanced at the factory for the larger bore/stroke 350 piston, I have a bad feeling about this combo, if this were my motor I would have the rotating assembly balanced. I know your tight on funds but this stuff is not adding up right, I never trust a previous owner so I would pull it apart and get it looked at. Do a google search for the casting number at the back of the block you will find some good articles

The main thing I am concerned about was weather it was a 4" bore, which indeed it is. Combined with a 350 crank and stock rods and it looks like I am good to go. The pistons I would think would be fine to put into a stock motor without it being balanced.

edit: Just did a leak down on the motor. Cylinder 2 was at %15, cylinder 4 was at %40. Looks like we are pulling the heads off this weekend. This motor is turning into a nightmare.

 

[Kwik_Cutty88]

Re: Budget Cutlass Build Thread, Making Progress.

Stripped the motor down tonight. Everything looked good, all 8 cylinder walls still had the cross hatch marks on them from the honing tool. Bore is definitely 4.00", I measured it 2 or 3 times lol. Heads need a valve job, going to look into that this week. All bearings looked good, as did the cam. We pulled the piston out of the cylinder that was at 40% and the rings did have some funny wear on them. So right now looks like just get a valve job done on the heads, throw some rings in it and it will be good to go. I'm gonna try to go with the highest quality rings I can get in my budget, and maybe just maybe throw a set of higher compression pistons in. After exact calculations it was at 9.22:1, I'd like to see it at 10:1 or 10.5:1.

All torn down

Quick picture of the heads, really are 1.94/1.50's, 76cc chambers.

 

[Kwik_Cutty88]

Re: Budget Cutlass Build Thread, Making Progress.

Some parts came in yesterday. Depending on what my check looks like next week hopefully I'll be ordering Keith Black pistions, and a summit re-ring kit. If not I'll just get the re-ring kit. Anyways here's what came in.

Oil pressure gauge and water temp gauges

This is what I'm thinking for gauge lay out, hopeful I can get it to fit. I was also going to paint the speedo and as gauge needles orange to match.

Jegs 6-3/4" balancer

Summit SFI flexplate

Comp Cams double roller timing chain

 

[BuWaGone]

Re: Budget Cutlass Build Thread, Making Progress.

Sounds like like you're back on track. Personally I wouldn't go much more than 9.5:1 on a iron headed street engine on pump gas. Glad to see you're goingtiming chain and doing away with the gear drive. Those gauges look like a tight fit. Not sure if you still have A/C but I put my water, volt and oil pressure gauges in a panel than went in place of the center vents. On another Cutlass I bought one of the bracket they sell and bolted it in place of the ashtray.

Lookin good though, wish I cou;d make your kinda progress in my Malibu wagon.

edit* just looked back in the thread and saw the A/C