302 rebuild

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Feb 6, 2012 | 02:32 PM

my93

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Mountain Pass

Joined: Feb 2003

Posts: 184

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302 rebuild

Getting ready to rebuild a 302 out of my 93 f150 truck and have some questions.

The engine is a stock 302 w/ roller cam (E7 heads) and mainifold. Cam performance not the best. The truck will be used for street/highway driving with some towing. Has E40d trans, 3:55 rear.

I have another "standard" roller block and intend to use that block and using my standard pistons/bore with my rebuild. What would be the "big" gain, if any, if I bored the block to .030 over and used 4 valve relief pistons without any other upgrades, as compared to the standard bore/standard pistons.

Now, suppose if I upgraded only the stock cam and using only the standard engine bore in lieu of boring 30 over would the upgraded cam be a better upgrade of performance than the stock cam used in a 30 over bore? Reason being the expense of new pistons and machine work for the .030 work etc.

How far can I go in upgrades using the stock computer and injectors.

Thanks

Feb 6, 2012 | 07:17 PM

Conanski

FTE Legend

Joined: Jun 2006

Posts: 31,930

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From: Ottawa, Ontario

A 30 thou overbore wont produce any noticable power increase on it's own but if you want the rebuild to last a reasonable amount of time this is certainly worth the cost. A cam change is the single best thing you can do to an otherwise stock motor, it will produce more power gain than any other single change on this motor. The stock injectors will support 300hp so that is the upgrade limit for the factory EFI system, after than you need mass air and a tuner to make the larger capacity components cooperate. A cam and full exhaust is nearly all that is needed to get to that level as well, the stock heads will stop progress at about 275hp and need professional porting to eclipse the 300hp mark.

Feb 6, 2012 | 07:25 PM

Boba Fett

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Conanski is right on....

Feb 17, 2012 | 08:51 AM

Bamadawg63

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Joined: Jun 2005

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You can get the machinist to measure your bore and if shes clean he can just hone it for a set of fresh factory pistons you can get from your local NAPA - they carry great OEM replacement stuff (Clevite, etc.). Some replacements can go as little as .010 or .020 over stock.

If you drop in a cam, gotta freshen up the entire head with new springs/retainers etc. You did not say what year the extra 302 roller block was? Like stated, the biggest gain lies with your top-end in the head/cam combo and a free-flowing exhaust. You could go with some long-tube headers - doesn't have to be dual's out the rear - just dump both headers into a free-flow cat then exit with 3" single pipe and a good flowing muffler of your flavor (lotsa people use a quality glasspack muffler cause they are cheap- the longer the muffler, the quieter the exhaust note in the rear).

http://www.lunatipower.com/Product.aspx?id=1653&gid=261

Nate

Feb 17, 2012 | 08:27 PM

baddad457

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Joined: May 2003

Posts: 11,141

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From: south louisiana

Quote:

Originally Posted by my93

Just a couple things here for your information: The pistons in your motor are flat tops with 4 valve reliefs, so no change there in your question about .030 pistons. And two, the 93's cam sucks, big time. Just a swap to the 94-97 cam will give it a kick in the pants, to the tune of about 25 hp. If you choose to keep the E7 heads, at least have the thermactor bumps removed from the exhaust ports, this is a simple operation that takes all of thirty minutes (total, for all eight ports) with a die grinder and good carbide bits. Also recommend a double row, roller timing chain set,(if it didn't have it already) this was the std set used on the HO motors of that era, you can buy these sets at the local parts house for less than $50. Last one I bought was $25 at O'Reillys about 4 years ago.