Cobra GT40 Heads & Cam options

[ross2004]

I have an '86 roller 5.0 engine and a set of factory stock 1993 GT40 heads off of a Cobra. While I'm doing the head swap I might as well put in a cam if I can, but I do not want to go to the trouble of changing the valve springs. My question is, can the GT40 heads from a Cobra (if that matters) with the 1.7 rockers handle anything more aggressive than the stock cam? Here's my setup and intended use, maybe a cam isn't even necessary...

'86 5.0 HO engine
'93 Cobra GT40 Heads
Edelbrock 289 performer intake (came with it, looking to trade up to an RPM)
Holley 600cfm carb (vacuum secondaries)
Factory Mustang headers
T5 transmission

Going in: 1987 BMW 325, ~2400 lbs. with 4.11 LSD rear-end. It's an endurance road race minded car to compete in ChumpCar and 24 Hours of Lemons. Looking for strong low-mid range power over high peak HP. Open to all suggestions, but not looking to dump a bunch of money into it. In reality a stock 5.0 HO is more than enough power for this car, but if the valve springs can handle a mild cam, I'll go ahead and do it.

Thanks!

 

[stykthyn]

to be honest you are likely going to have piston to valve issues with those heads and the stock cam on 86 flat top pistons.

 

[ross2004]

Ok that's good to know. Good thing we have the 1.6 rockers too I guess; thanks for the reply!

 

[stykthyn]

seriously mock the heads and use clay to see if they hit. 90% chance they will regardless of rocker. 87+ cars cam with valve reliefs. would likely be cheaper to scrounge and explorer short block. Swap out the cam and bolt on your heads/intake. Bam you are done.

 

[ross2004]

I will definitely clay the engine to check PTV clearance; anything special about clay'ing these engines?

 

[foxna6]

Your more then likely gonna need to cut reliefs in the pistons for the heads to work let a lone with a cam with some lift

 

[ross2004]

In case anyone comes across this thread in the future: the pistons DO hit, with both 1.7 & 1.6 rocker arms. Now time to price out the options...

 

[old_blue]

good to know with those that have the same issue.

 

[Gearbanger 101]

This is likely to be your cheapest and best option....

http://www.thunderracing.com/shop-b...ain-Tools/Isky-Piston-Notching-Tools_455.html

 

[ross2004]

Thanks for everyone's help- we found a 5.0 HO out of a '90 Lincoln Mk. VII at the junkyard with 95k miles on it for $275. Going to use it and sell the '86 motor. Should break even on the deal so no big deal.

Now, back to the original question. Are there any aftermarket cams that will work without upgrading the valve springs? How about a B cam? We'll have both 1.6 & 1.7 rocker arms available to use.

 

[stykthyn]

Find a cam that fits your application and measure the lift against wh at the springs are rated for. At 95k miles valve springs are cheap insurance against valve float.

 

[ross2004]

Isn't there more to it than just lift, though?

 

[chrisds302]

Edited, use the classifieds

 

[ross2004]

Where are you located? With shipping might not be worth it to us.

 

[chrisds302]

im in indiana how about you? i really dont know what shipping would be i can find out though?

 

[chrisds302]

b cams 190$ new unless you have one already ? engine has less than ten K on it

 

[ross2004]

VA. If it's just the short block I'd still need valve springs in the heads to use the B cam. Thanks for the offer, but I think we'll go with the junkyard engine so we have all the accessories and other little bits and pieces.

 

[golf4283]

Chris where in Indiana are you? I'm in the market for a short block and live in the south suburbs of Chicago.

 

[san~man]

Do not turn this into a sales thread and get it locked.