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Discussion Starter #1 (Edited)
I checked some threads, but didn't find the exact info needed. I have a 79 block, .030, with .012 cc recessed pistons, all together. Cam is Lunati barebones cam (.214/.224 @.050, .472/.496 lift), and matching springs (~115 lbs closed?), 1.7x roller rockers, 8.15" hardened pushrods, hosed up my 70W heads and saw some new/bare/iron GT40P's for $200 on eBay. Any idea if my valve springs and pushrods could be used? Where to pick up the valves, and what lengths should they be for 351W setup? Any assistance would be great. Those exhaust ports look so much wider, and the guy selling the heads stated the intake flow would be around 200cc / 145cc intake & exhaust at .500 lift. Any smog shiite to worry about with them? BTW, I read GT40's are better than GT40P's but what are the benefits? Also see GT40 aluminum heads on eBay for around $550 (per head-false advertising f'er) with valves and springs. Should I just go that route? Realize I'd need to take these head types to a machine shop to accommodate 1/2" head bolts. Also, forgot to mention that I have the performer dual-plane Edlebrock manifold, and 600 cfm Edelbrock carb, or a 980 cfm Holley. Eric.
 

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'79 block will have 9.503 deck height. GT40s have 64cc chambers. GT40Ps have 58cc. Cast iron GT40Ps as cast flow better than non-Ps due to revised plug location/angle. Once you get into the FoMoCo aftermarket aluminum GT40s though, all bets are off.

I can tell you that with my 9.503 block, 22cc dished pistons and 64cc heads, I'm at 9.5:1 compression. About as high as I want to go on 87 or 89 octane pump gas with my cast pistons. With 12cc pistons you're well over 10:1 with 64cc heads. Get into 58cc heads, and you're talking closer to 11:1.

Ford Motorsport GT40 aluminum heads are already made for the 351W's 1/2" head bolts.

OK, that Lunati cam... was that .472/.496 lift with 1.6 or 1.7 rocker arms? 1.7s will gain you approximately .03x lift over 1.6s at that lift level.
 

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Discussion Starter #3
The specs for the cam were based on 1.6x standard rockers, so the exhaust lift should be .526ish. Nice thing is that I have racing gas just a few miles away - good old Slinger raceway fastest 1/4 mile track around.
 

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Claiming that the GT40P flow 200 cfm / 145 cfm @ .500" might be a little exaggerated. Here is some flow bench information on a large number SBF heads. http://cougarowners.com/index.php/techinical-articles/61-302-351w-head-swap-information.html

I've seen a lot of guys buy "nice" used heads just to get screwed at their mechanic. After getting them reconditioned with a fresh 3 angle valve job, some new valve guides, seals and maybe a valve or two, they ended up spending almost as much money as a new assembled set of Edelbrock Performer RPM heads. Call around to your local machine shops to see how much they will charge for a performance valve job before you buy anything.
 

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Discussion Starter #5
Could anyone direct me to some good intake/exhaust valves for the GT40P's? The guy who had the heads on eBay directed me to Precision Engine Parts out of Las Vegas, but after a week I've received no reply to my inquiry on price...

I'll be taking them to NVR Racing in Butler WI to increase the head bolt holes and tap the stud holes ($150 quote). Would like to know also if the valves are same height as W's (impact from 1.7x rollers?). I think I read at some other forum that the exhaust valves had different tip lengths where the keepers are located. Finally, would the Lunati barebones spring kit would work with these heads/valves (LUNATI 1.450" SB FORD VALVE SPRINGS KIT #73084K1LUN - http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=140548659895&ssPageName=STRK:MEWNX:IT).
 

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$150 for just the head bolt ream and the tapping? Seems very pricey to me.
 

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Just buy some fully assembled heads. It'll be cheaper and easier for you.
Also, they will flow better. Check out the flow numbers in that giant chart. When you buy new valves for your heads, you will need a complete valve job. The valves angles will not match your seat angles. For about $600, you can get a good set of Edelbrock RPM heads. This will match you setup pretty well and will save you at least $200, but probably a lot more.

Installing valve springs correctly isn't as easy as just popping them on. You have to get a valve spring tester and a valve spring mic. Good ones can be expensive. You have to shim them properly to get good results.
 
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