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Bigger lifter bores gen 1 sbc

General engine tech -- Drag Racing to Circle Track

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Little Mouse
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Bigger lifter bores gen 1 sbc

Post by Little Mouse » Sat Oct 26, 2019 6:15 pm

I have both a 68 and 70 year model blocks lying around they checked out ok to use. I'm one of those that just likes the simplicity of the solid flat tappet cams. Is there enough material strength around the lifter bores to use a .904 size flat tappet. Just eyeballing them it looks like it might work.

Charliesauto
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Re: Bigger lifter bores gen 1 sbc

Post by Charliesauto » Sat Oct 26, 2019 7:19 pm

Little Mouse wrote:
Sat Oct 26, 2019 6:15 pm
I have both a 68 and 70 year model blocks lying around they checked out ok to use. I'm one of those that just likes the simplicity of the solid flat tappet cams. Is there enough material strength around the lifter bores to use a .904 size flat tappet. Just eyeballing them it looks like it might work.
Yes

BLOCKMAN
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Re: Bigger lifter bores gen 1 sbc

Post by BLOCKMAN » Sat Oct 26, 2019 7:20 pm

I have done quite a few of those 010 blocks .875 and .904 and not get into water. If your going to have them machined to .904 have them by some using a CNC machine for the best results. Fixtures don't seem to be that accurate from what I have seen.

Sonic test your blocks before spending any money on them and don't go by core shift its very misleading compared to a sonic tester.

Going to flat tappet the lobes will have to be narrowed and in most cases those cams I have seen will break on the rear in front of the last lobe, On the engines I build with .904 flat tappet lifters I now go to a BBC journal it works ever time.

One of my customers would use a .030 shim in back of the cam gear and pull the cam a head in stead of narrowing the lobes it always worked for him. Just created faster lifter rotation.

Good luck

JodyB
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Re: Bigger lifter bores gen 1 sbc

Post by JodyB » Sun Oct 27, 2019 1:01 am

What is the application? Max rpm and what valvespring pressures do you intend to use? Big lifter bores are not low hanging fruit in hp per $ with SFT until you are pushing the envelope a bit.

BLOCKMAN
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Re: Bigger lifter bores gen 1 sbc

Post by BLOCKMAN » Sun Oct 27, 2019 9:04 am

JodyB wrote:
Sun Oct 27, 2019 1:01 am
What is the application? Max rpm and what valvespring pressures do you intend to use? Big lifter bores are not low hanging fruit in hp per $ with SFT until you are pushing the envelope a bit.
Better cam profiles using bigger flat tappet lifters.

Little Mouse
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Re: Bigger lifter bores gen 1 sbc

Post by Little Mouse » Sun Oct 27, 2019 4:27 pm

If I tell you the application you will all hate me lol. Just want to do very high rpm 337. O60 over 327 using a 1970 block I have it does have the slightly better
Nodular caps on it. Will have to be kept at pump gas compression despite the loss. Hell if your doing a 327 you already picked a loss in power lol. As far as the cam no doubt when it comes time to get it will be contacting mike jones for it. Will want proferial cam core and use a little lighter hollow stem valves and will want to use springs that are light in weight but good enough for the job and tool steel retainers.While at it talk about cam stuff can an LS firing order be done on a flat tappet cam. My understanding that fireing order is easier on the crankshaft and bearings. Only 327 I built many moons ago was .030 over at . I'm considering the thought of using a fill in the block only up to the bottom of the freeze plugs, should help stiffen the thin bores some. Want to use iron heads going to do darts 49cc chamber 21 1/2 degree with most likely mahls 21 degree pistons. Tires should end up 29 dia. Will do at least 4.56 rear but most likely at that dia. Beleive will do 4.88. Have CDL license so a car that might do135 or so on the freeway a no no get me in trouble. So will just run to 80 or so for my jollies and take it to the strip few times a year. I'm old school high rpms on the freeway does not bother me. Not like the car will be daily driver.

BLOCKMAN
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Re: Bigger lifter bores gen 1 sbc

Post by BLOCKMAN » Sun Oct 27, 2019 6:12 pm

Little Mouse wrote:
Sun Oct 27, 2019 4:27 pm
If I tell you the application you will all hate me lol. Just want to do very high rpm 337. O60 over 327 using a 1970 block I have it does have the slightly better
Nodular caps on it. Will have to be kept at pump gas compression despite the loss. Hell if your doing a 327 you already picked a loss in power lol. As far as the cam no doubt when it comes time to get it will be contacting mike jones for it. Will want proferial cam core and use a little lighter hollow stem valves and will want to use springs that are light in weight but good enough for the job and tool steel retainers.While at it talk about cam stuff can an LS firing order be done on a flat tappet cam. My understanding that fireing order is easier on the crankshaft and bearings. Only 327 I built many moons ago was .030 over at . I'm considering the thought of using a fill in the block only up to the bottom of the freeze plugs, should help stiffen the thin bores some. Want to use iron heads going to do darts 49cc chamber 21 1/2 degree with most likely mahls 21 degree pistons. Tires should end up 29 dia. Will do at least 4.56 rear but most likely at that dia. Beleive will do 4.88. Have CDL license so a car that might do135 or so on the freeway a no no get me in trouble. So will just run to 80 or so for my jollies and take it to the strip few times a year. I'm old school high rpms on the freeway does not bother me. Not like the car will be daily driver.
Spend money on a sonic test before spending any money on the OEM block

Little Mouse
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Re: Bigger lifter bores gen 1 sbc

Post by Little Mouse » Tue Oct 29, 2019 12:04 am

Will do this.

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Re: Bigger lifter bores gen 1 sbc

Post by Krooser » Wed Oct 30, 2019 10:24 am

Watch fleabay for Ti valves....I bought two sets for about $75.00/16 a couple years ago. Xceledyne brand. 6/7 mm stems.
Luxemburg Speedway Hall of Fame Member Class of 2019

SMITHBERGRACING
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Re: Bigger lifter bores gen 1 sbc

Post by SMITHBERGRACING » Fri Nov 08, 2019 12:00 pm

Little Mouse, from reading your posts my thread may interest you.
https://www.jalopyjournal.com/forum/thr ... d.1085889/

Little Mouse
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Re: Bigger lifter bores gen 1 sbc

Post by Little Mouse » Fri Nov 08, 2019 11:32 pm

SMITHBERGRACING wrote:
Fri Nov 08, 2019 12:00 pm
Little Mouse, from reading your posts my thread may interest you.
https://www.jalopyjournal.com/forum/thr ... d.1085889/
Ya cool build.

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