ref 302

[modxl]

after messing up and buying a 74 smog motor ive managed to find another motor,which are few and far between here in england at the right price.Its got gt40p heads so is it a explorer motor also whats the fit like with these heads in a gen 1 ranger

thanks guys
steve

 

[dangerranger83]

Thye fit nicely in a Gen1 ranger.

Use the search function to find 302 swaps here, ther are alot of them.

 

[modxl]

it was the heads i was more concerned about because of the headers being different to normal a 302
steve

 

[baddad457]

You'll have to choose your headers wisely, as the funky plug angle is a problem with most headers

 

[shane96ranger]

You'll have to choose your headers wisely, as the funky plug angle is a problem with most headers

Can you use factory Explorer manifolds?

 

[baddad457]

Can you use factory Explorer manifolds?

I'm sure you can, but why ? May as well keep the V6.

 

[shane96ranger]

I'm sure you can, but why ? May as well keep the V6.

LOL. They are a start if you have them, and are on a budget though.

 

[modxl]

cheers for replys lads,deal with explorer motor gone tits up.So question is what can i do with this smog motorto get a few more ponys out of it,i now a set of flat tops will help but what else do u suggest with out to much machine work.sure i have seen some were that later 5litre have a slightly taller pin to top of piston hieght is this right
steve

 

[baddad457]

Yea, watch your pin heights, not all 302 flat top pistons are the same. The pin heights vary from 1.585 to 1.620 . The shorter height will fall well short of the deck at TDC in your block. What you should do is buy the taller pistons, then after the block is bored, assemble one rod and piston, seat the crank, then drop the piston and rod in each of the four corner cylinders and measure the deck clearances, then have the block's deck milled to achieve a zero deck with those pistons. There's nothing wrong with your block's vintage, they're good blocks, you just need to pay attention when buying pistons for it. As it is now (if it's never been rebuilt) it's got pistons with a huge, grand canyon sized dish in the piston top, these pistons were used from 72 to 76 in the 302.

 

[modxl]

thanks mate guessed that would be the way to go,i have just found some domed pistons and spec says with my deck height and 54cc heads 10.53 comp ratio,well i have 58cc so compression going to be in the high 9s i would think what do u reckon
steve

 

[baddad457]

thanks mate guessed that would be the way to go,i have just found some domed pistons and spec says with my deck height and 54cc heads 10.53 comp ratio,well i have 58cc so compression going to be in the high 9s i would think what do u reckon
steve

The extra 4 cc's are only going to change the ratio by one half point in a 30 over 302. What domed pistons are you looking at ? Just adding the swept volume and the gasket and chamber volume, I came up with an 11 to 1 ratio. A 6 cc dome would up that to 11.6. A zero deck flat top with a 9 cc gasket (.040) and a piston volume of 5-6 cc's (this is about average for a 4 relief flat top, plus the area around the piston down to the top ring) will give you a 9.6 ratio.

 

[modxl]

hi mate after a bit more research ive found a couple of options piston wise,
no1 is a doomed piston L2249NF+60 only do this doom in std or 60 oversize gives me 10.78 comp/58cc heads
no2 is a flat top piston L2488F+30,with a 1.619 compression hieght and that gives me 9.53 comp/58cc heads
not sure what to do at minute didnt really want to take block out +60 as block still std bore needs rebore but thats going straight to the limit and cutting it fine.Option number 2 looks good to me if have head skimmed a bit gives me not bad comp ratio what do u think as you seem to now these motors better than me
steve

 

[baddad457]

I too would not go 60 over on it, over here it's OK, as there are still lots of blocks available if things go south with the walls that thin. If it's still got the cross hatch pattern in the walls, I'd just hone it and go std size with the pistons. As for the comp ratio, if you can afford the cost of feeding it premium fuel (I've got no idea what you all have over there as far as octane grades) then go with the higher ratio. If not, then go with the lower ratio. Now all that aside, the 60 overbore is never an option with the roller blocks, but your 74 should be OK with it, depending on the core shift of the cylinder jugs. A 30 overbore is a nearly always OK for that year block.

 

[modxl]

hi mate,block needs a rebore as well worn,going flat top 30 over,with the higher compression height and getting a few thou taken of the heads.I believe or gas octane rating is a bit higher than yours in the states,or unleaded is about 96ron and our super 98,also may be running it on lpg which runs about 100 ron,have several cars on lpg and a good friend that fits it for a living,so install very cheap,got a 4.3 astro on lpg and it loves it so does my wallet gas prices over here are so high at about 6.72 a gallon thats about 10 dollars a gallon,hopefully state some build pics in a few weeks,got some body work to do as well as engine rebuild install just waiting for some prices for rear wheel arch repair panels,because our uk importers like to over charge for stuff because they now not many companys in the states will ship panels to the uk,as well as over stuff,like i found out last year driver door glass,foud new in states about 80 dollars i think no one would ship so had to get one from uk importer 340 dollars,so you see what we have to put up with for our love of american autos

steve

 

[baddad457]

If you're going to feed it LPG, then go with the popups and the higher comp ratio. The LPG would perform better with the higher ratio.