General 302 questions

[curtis73]

Howdy all. I'm a new guy to the list and have some questions. I am a big fan of modifying. I usually have very odd ideas when it comes to mods, especially with engines. I have a 66 Bonneville with a Caddy 500 in it, and an 85 El Camino that will soon be a convertible with a Hemi 528.

I have an 87 Cutlass Salon and I have some wierd ideas for it as well. On the Olds G-body list there is a "fad" of a few guys modding the heck out of their 307 olds engines. They've been very successful, but they are dealing with very non-performance oriented dimensions. Small bores, wasteful heads, and lack of aftermarket parts that work with the small displacement are a problem. I've always loved the ford 5.0 and I want my Cutlass to have a 307...a Windsor, that is.

My main obstacle is going to be the oil pan. Was there a Windsor with a rear-sump pan? Trucks? I can modify an existing pan to fit my chassis, but if I start with a rear sump it will be easier. Who knows, it may fit like it is.

When did 302s start using roller hyd lifters? Are the blocks the same, just different lifters...or were the lifter bores taller/different diameter? I want rollers, so should I worry about what year core I get, or will any one be easy to modify?

What are the 302s big handicaps? For instance, Olds engines have weak main webs, stock buicks had weak oiling, stock pontiacs had weak valvetrains. What is Ford's weakness?

What's the bore and stroke?

Looking forward to making people sick with my five-oh Cutlass...

Thanks
Curtis Mittong

PS. Yes, I am mentally sick

[PKRWUD]

Hi Curtis, welcome to the site! I'm afraid I can't help you much, but I do come from a long line of modified Olds 403's. I had one in my 77 LeSabre that rocked the world. Just something to consider.

Take care,
-Chris

[Unit 5302]

The HO engines got front and rear sump pans with the front sump being much smaller than the rear on the later Mustangs. There may be rear sump 302's out there, but I'm not sure.

The roller cam was first placed into the Mustang 5.0 in 1985. The 5spd that year got a Holley 4bbl and a a roller cam. All Mustang 5.0HO's after that had the roller cam. The blocks are different. Slightly shorter lifter bores in the older, non-roller blocks, but there are conversion kits out there.

The 302 has weak main webs as well. The stock HO blocks with stock rotating assemblies will do fine with 450-500hp. Beyond that, you could lose it. Properly setting up and balancing the setup will allow you to stay cool up near the top of that range, and maybe a little beyond depending on your luck. There are stronger blocks out there for the 302, but they are hard to come by, unstreetable, or expensive.

Bore/Stroke is 4"x3". A common .030 overbore will bump the 302 out to a 306, not a 307.

[curtis73]

Unit 5302 says::::Bore/Stroke is 4"x3". A common .030 overbore will bump the 302 out to a 306, not a 307........


Crap. I'll bet a .040" overbore makes a 308. Oh well. I'll get it close and call it a 307, but use a Fox-body "5.0" emblem. I even have ideas about grafting the top half of an HEI onto a Ford distributor shaft. That will really throw people off. I can see it now; "is that a Buick? Caddy?" I'm also going with an EFI setup, but I'll plumb it into a carb manifold or maybe a hilborn stack. The factory EFI is too much of a dead giveaway.

I guess if I'm nervous about the bottom end I could use a main girdle thingy.

I assume (since the newer blocks are roller cam) that the 5.0 blocks sold in Summit are for rollers. They are advertised as "some of the last 5.0 blocks before the switch to 4.6," so I assume they are. They seem like a steal at $300 but maybe that's just me.

OH.... I almost forgot. Any factory 5.0s with aluminum heads? If so, are they a good choice to modify, or should I spring for Twisted wedge or Edelbrock heads?

Thanks for the info. Keep it coming!

Curtis

[Mach 1]

I think those $300 blocks from summit require machine work to finish them up. I dont think they are bolt in ready.

[MiracleMax]

All of the pre-79 stuff was rear sump I believe, delfinitely the early seventies stuff, Ford went to the double sump pan when they started using a k-member and rack & pinion.


Ever thought of using a 350 olds motor? got and excellent bore to stroke ratio (crappy blocks from what I understand, but I'm guessing they are certainly comparable to the 5.0 block in terms of strength), however you'll be bucks ahead by using the 5.0 and the envy of GM guys everywhere :

Oh father Frankenstien grant me the resources to build a windsor powered 67 nova one of these days!

[curtis73]

Yeah, I've thought about an Olds motor. Pretty much any GM family will drop in with a careful selection of motor mounts and accessories: buick, olds, chevy, pontiac, caddy. All of them (except caddy) were used in the G-bodies. Of all of these, the Olds and Pontiac are my two least favorite. The Pontiac is pretty heavy and both the Poncho and Olds have small bores so they hurt for breathing. You are right, the 350 olds and the 403 have great dimensions, but really crappy bottom ends. The Caddy is one of my favorites: huge displacement, high nickle content, cheap cores, and not much heavier than many small blocks.

For every project I come up with objectives. My 66 Bonneville was going to be a tow vehicle, so I wanted major stroke, huge displacement, low rpms, and respectable mpgs. I used the caddy 500 with a mild cam and it makes about 600 lb-ft at 1500 rpms, and 390hp all before it hits 3500 rpms. I also used an 8-lug, 14 bolt rear axle from a 2-ton truck. It hauls alot and gets 18mpgs.

This Cutlass is a daily driver, 100 mile commutes, 28k a year, and a few cross country jaunts each year. It needs to get about 15-20 mpgs, have very common off the shelf parts, and be easy to repair while having easy bolt on performance parts. So I'm looking at the most "common" possible engine. This screams for a 350 chevy, but I refuse to put a chevy in my car. That is too blah. The next most common would have to be a 302, so I'll either mod the 307 thats in it, or use a 5.0 ford.

[chris91LX]

If you get a 350 and stroke it to a 383 you can use 302 pistons, that's what i heard at a local engine shop yesterday anyway.

[mean81GT]

the summit blocks are ready to build. they come with honed a prep, ready to build. but they are stock 5.0's, nothing special. hey, this cutlass would be sweet. how many rodders build 32 deuce coupes, and put chevy 350s in them? we'll get one back here, boys!

[PKRWUD]

Originally posted by MiracleMax
All of the pre-79 stuff was rear sump I believe, delfinitely the early seventies stuff, Ford went to the double sump pan when they started using a k-member and rack & pinion.

The small block Ford was never a rear sump engine. The Fox body sump is the farthest back it ever got.

Take care,
-Chris

[curtis73]

Yeah, I can buy the block for $299 plus freight (unless I swing through OH on my way back to PA, then I could pick it up) I'd get some good Twisted Wedge heads for about $1000 ($700 if I can find them used) and a forged piston rotating assembly from PAW for about $700. Roller cam and lifters, $300. Intake and carb (to start...EFI later) for another $300. I'll get everything else from a junkyard; distributor, flywheel, tranny, etc.

I may get cheap and buy a junkyard core.

Hey...a couple questions. In PAW's catalog, they list rotating assemblies in very specific increments. Like, 69-84, then very specific dates in certain years; 1/10/84 - 5/11/86, 87-88, etc. What's the scoop?

85 started roller cams.
What years used forged pistons?
What year started one piece rear mains?
Factory Aluminum heads: what models and are they any good?

Curtis

[Mach 1]

Forged pistons were through 92', but Im not sure what year they started.

The 5.0 never had aluminum heads.

One piece rear main seal started in 82 I think?

[curtis73]

So if I get a core between 85 and 92, that will get me a roller cam, one piece rear main, and forged pistons. Cool.

What were the GT-40 heads? Just aftermarket from MOtorsport?

Curtis

[Mach 1]

Yes, the gt4o heads are available from Ford motorsports, but came factory on the 93' - 95' mustang cobra and the 93' - 95' F150 lightning.

[curtis73]

Are the GT40s as good as, better, worse, than twisted wedge or edelbrock heads? Were they used enough that finding junkyard cores is likely? What can one expect to pay for a set?

Curtis

[Coupe Devil]

You might be crazy to others but to me your an automotive pioneer man. As far as the bottom end being weak on a 302, look around and find a 86 model block. Ford made the main webs .030 thicker this year. They wanted to add alittle strength but it cost to much in the long run and They only did this for one year. get your self a good set of Forged pisons, good h-beam rods (steel), and a set of trickflow heads. You'll be set.

Brad

[MiracleMax]

Hah, your right PK, I musta been hoping against hope to see a Ford product in a GM

[Mach 1]

the twisted wedge and edelbrock are better than the gt40's, and the way to go in my opinion, unless you are really on a tight budget. You can also use the explorer 5.0 "P" heads? and they are cheap and equivelant to the gt40s, but require a special header I believe due to spark plug angle.

Im sure somebody on this board knows more about the p heads than me.

[Unit 5302]

To my knowledge, the 1985 roller engine did not have forged pistons. I believe it had dished cast pistons. You certainly don't want a 1986 if you're gonna try to use the stock pistons. 1986 did have forged pistons, but they are flat top and do not have valve reliefs. The 1986 engine will require a piston change to run anything more aggressive than the 1987-1995 stock HO heads. You will also not be able to cam the 1986.

If you're trying to find the most versatile roller cam engine, the 1987-1992 should be your selection.

They had forged pistons with valve reliefs and the roller cam.

The GT40 heads can only be found on the 1993-1995 Cobra, and the 1993-1995 Lightning, to the best of my knowledge. Your chances of finding a set in the junkyard are slim to none, and if you did, they'd cost you a pretty penny.

The GT40P heads flow better than the original GT40 Cobra heads. Dispite the smaller exhaust valve size, a better port design. and the removal of most of the exhaust thermactor valve bump allows the P heads to flow better. About 195cfm intake/140cfm exhaust at .500. They also have a smaller combustion chamber size than stock or GT40 heads allowing for higher compression. The GT40P heads will give you about 9.5:1 CR on a stock 1987-1995 engine, and the GT40's will drop it to about 8.8:1. Between the two, the P heads are better, and they generally cost less. About $500/pr assembled. Both types of GT40's are iron.

The GT40 series heads are not as aggressive in flow as aftermarket aluminum heads.

[Unit 5302]

Since you should be buying headers regardless of whether or not you're using the P heads, I don't see the fact they require special headers to be a real big issue.