How to: Compression. oppinions?
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How to: Compression. oppinions?
Was wondering , I would like 9.5-1 compression for my '73 350 project engine. Am I better off to #1, use flat top pistons & a set of 76cc heads, Or #2, Use the stock dished pistons & 68cc heads?
benefits or bad for either way? Oppinions/advise please.
benefits or bad for either way? Oppinions/advise please.
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From: Waterford Mi
When I rebuilt my engine I found that the deck height was almost 0.035" which means with the stock dish pistons and heads and 0.040 gasket, I was almost <8:1 instead of the advertized 8.5:1. I went with flattop pistons and 64cc heads just to get 9.6:1.
Le Mans Master
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From: Little Rock AR
Originally Posted by Glasspacked
Was wondering , I would like 9.5-1 compression for my '73 350 project engine. Am I better off to #1, use flat top pistons & a set of 76cc heads, Or #2, Use the stock dished pistons & 68cc heads?
benefits or bad for either way? Oppinions/advise please.
benefits or bad for either way? Oppinions/advise please.
If the bores are trashed too far and need to go .030 oversize, you want flat tops and better heads to match the rest of the combo.
I just hate to see perfectly good parts going in the trash.
-Mark.
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research
It seems the more research I do, the more it looks like what is needed is a dome Piston (.100 dome) & 76 cc heads. gets it right to 9.5-1 .That way I don't have to buy BOTH pistons & heads. has anyone tried this approach?
Le Mans Master
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From: Little Rock AR
Originally Posted by Glasspacked
It seems the more research I do, the more it looks like what is needed is a dome Piston (.100 dome) & 76 cc heads. gets it right to 9.5-1 .That way I don't have to buy BOTH pistons & heads. has anyone tried this approach?
SPEND MONEY ON THE HEADS is always a good rule when modifying an engine. Cam it to match the application and enjoy. Otherwise the heads will always be the limiting factor down the road.
-Mark.
Le Mans Master
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From: Little Rock AR
Originally Posted by Glasspacked
# 3973487 heads prone to cracking ?? I know #882 & #624 are known to be thin wall & prone to cracking, but never a bad word about 487. Have you experience with these?
-Mark.
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concidered the camel hump heads
I thought about the old "fuelie heads" but can't use them because of the lack of holes in the end of the heads. & the difference of $200 for a completely fresh set of 487s, & the price of Darts or aluminum puts them out of my budget. With those heads & the .100 dome pistons get it to 9.5-1 compression, (the pistons I've alredy got.)
Le Mans Master
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From: Little Rock AR
"186" Fuelie heads have the holes in the ends but those are a little harder to get. I have them on my Camaro. 
"041" heads are the same as "186" heads but they do not have the double humps so they sell for less. 
Just a little thing to keep in mind when looking around at swap meets.
Either way, it sounds like you have a good plan.
-Mark.
"041" heads are the same as "186" heads but they do not have the double humps so they sell for less. Just a little thing to keep in mind when looking around at swap meets.Either way, it sounds like you have a good plan.
-Mark.
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Don't buy heads on ebay
I bought a set of supposedly 487s on ebay. what I got was 1- 487 & 1- 993. the 993 has a crack from the center bolt hole up between the 2 center cyls., 4 sunken valves, 35 year old valve springs,& cast grey paint over grease. (These were advertised as totally recond., 3 angle,.550 LIFT new springs, ready to bolt on) I called the vender, Shawn Anderson of "southern Cylinder heads" 256-535-4403 (using sda316as a seller name) in Alabama to see about getting replacements, & was pretty much told to f- off. & I was stuck with them. so, if you are thinking of buying heads on the internet, BEWARE.
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From: Orlando Florida
St. Jude Donor '05
Originally Posted by Glasspacked
I bought a set of supposedly 487s on ebay. what I got was 1- 487 & 1- 993. the 993 has a crack from the center bolt hole up between the 2 center cyls., 4 sunken valves, 35 year old valve springs,& cast grey paint over grease. (These were advertised as totally recond., 3 angle,.550 LIFT new springs, ready to bolt on) I called the vender, Shawn Anderson of "southern Cylinder heads" 256-535-4403 (using sda316as a seller name) in Alabama to see about getting replacements, & was pretty much told to f- off. & I was stuck with them. so, if you are thinking of buying heads on the internet, BEWARE.
You really have to take the time to go to their feedback page and see what they sold .. some sellers never sold anything but got a lot of good feedback for buying cheap stuff on ebay, then when the feedback rating is good they try to sell their junk....
There are sellers that have 10000++ feedbacks and 100% positive....
this seller sda316 has only 29 feedbacks
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fufurther inspection
Looking even more closely, On one head there are valve rotators on the exaust & none on the other head! never heard of a "small block with valve rotators, (& then ,only on 1 head) I did look at his feedback. was all good.