Technical engine stuff (put on thinking caps)
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From: Middlefield CT
Technical engine stuff (put on thinking caps)
OK, According to people on the forum I have a 68 327ci (VII28YA 646332) from a truck in my 71 vet. Here are the technical questions, is it a 4 bolt main and can I make it into a 383? I think the bore is 4.000?? Is it only the stroke a I need to change and go .030 over? Will this block support a 383 (3.75 stroke with 5.7" rods)?
Race Director
Joined: Mar 1999
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From: Calif.
Re: Technical engine stuff (71 Red Sled)
OK, According to people on the forum I have a 68 327ci (VII28YA 646332) from a truck in my 71 vet. Here are the technical questions, is it a 4 bolt main and can I make it into a 383? I think the bore is 4.000?? Is it only the stroke a I need to change and go .030 over? Will this block support a 383 (3.75 stroke with 5.7" rods)?
2. If the bore is 4" you will have to enlarge it to 4.030" and add the stroker crank.
3. If the block is sound you will have no problems building a 383.
Safety Car
Joined: Aug 2000
Posts: 3,711
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From: San Antonio TX
Re: Technical engine stuff (The Dude)
Four-bolt mains were a no-show in smallblocks until 1969 so there is no such thing as a factory 327 four-bolt. Your '68 327 block is a large journal type and sharing the same 4.0" bore as a 350 (and 302), sure you can stroke it to a 383. You get the 383 with a 3.75" crank and a 4.030" bore. The rod length has nothing to do with displacement.
1st Gear
Joined: Aug 2002
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From: st paul mn
Re: Technical engine stuff (gerry72)
1968 was a breakover year for the SBC. '68 327s had larger journals on crank and rods than the '67 and previous engines. I believe that 4-bolts came with the big journals. I have a 275hp 327 in a 68 Impala... I can't imagine that it would only be a 2-bolt block... but I haven't pulled the pan, so I could be wrong. My knowledge is research-based, not experience-based. :confused: This is my first post- please be nice to me :D
Safety Car
Joined: Jul 2002
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From: St Louis MO
Re: Technical engine stuff (71 Red Sled)
**
I thought all truck blocks were 4-bolt mains. I don't understand what all the hype is on 4-bolt mains. Only if you're churnin over ~500 HP are they really needed. You'll need the 350's 5.7" rod for better rod/stroke ratio. The lower the ratio, the better off you are.
I thought all truck blocks were 4-bolt mains. I don't understand what all the hype is on 4-bolt mains. Only if you're churnin over ~500 HP are they really needed. You'll need the 350's 5.7" rod for better rod/stroke ratio. The lower the ratio, the better off you are.
Burning Brakes
Joined: Jul 2001
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From: Ajax Ontario
Re: Technical engine stuff (gerry72)
Four-bolt mains were a no-show in smallblocks until 1969 so there is no such thing as a factory 327 four-bolt. Your '68 327 block is a large journal type and sharing the same 4.0" bore as a 350 (and 302).
Safety Car
Joined: Aug 2000
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From: San Antonio TX
Re: Technical engine stuff (Brettmc)
**
...You'll need the 350's 5.7" rod for better rod/stroke ratio. The lower the ratio, the better off you are.
...You'll need the 350's 5.7" rod for better rod/stroke ratio. The lower the ratio, the better off you are.
Le Mans Master
Joined: Jul 2001
Posts: 9,622
Likes: 16
From: absecon nj
Re: Technical engine stuff (gerry72)
they are correct 2 bolts till 68 then 4 bolts came out in 69,i had a 68 327 i ran in my 76 for 2 years twice a week at atco,ran it to 7000 every time held up fine.but if your gone to stroke it go for the longer rod like gerry said if your gone to spend the money do it. and if you didnt want to bore it out leave it standard for a 377ci.
[Modified by pats406nitrovette, 2:53 PM 8/9/2002]
[Modified by pats406nitrovette, 2:53 PM 8/9/2002]
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Joined: Sep 2001
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From: Middlefield CT
Re: Technical engine stuff (71 Red Sled)
You guys are great..... It's like having an army of experts at my finger tips. I was kinda bummed about the 240 hp 327 engine, but now I can't wait til winter to tear this bad boy down and shoot for 450 hp.
-Tony
-Tony
Burning Brakes
Joined: Jul 2001
Posts: 1,160
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From: Ajax Ontario
Re: Technical engine stuff (71 Red Sled)
You can make good power from a fairly stock 327 even without stroking it as you suggest. L79vette has a real strong 327 that dynoed around 275rwhp, which would be well over 400 using the old "gross" ratings! You should be able to easily top that with the 383!
Safety Car
Joined: Feb 1999
Posts: 3,630
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From: Fountain Hills AZ
Re: Technical engine stuff (Brettmc)
**
I thought all truck blocks were 4-bolt mains. I don't understand what all the hype is on 4-bolt mains. Only if you're churnin over ~500 HP are they really needed. You'll need the 350's 5.7" rod for better rod/stroke ratio. The lower the ratio, the better off you are.
I thought all truck blocks were 4-bolt mains. I don't understand what all the hype is on 4-bolt mains. Only if you're churnin over ~500 HP are they really needed. You'll need the 350's 5.7" rod for better rod/stroke ratio. The lower the ratio, the better off you are.