Michael Yount

LS3 in my 1982 Volvo 242 -- FWIW, I just hooked the canister up to the inlet air piping through a barbed fitting -- placed in between the air filter and mass air sensor. No gasoline fumes at all, tank vents as it should -- works just fine. Left the purge valve completely off and capped the fittings.

Well, not a Z, but it will provide another data point. 82 Volvo 242, 2980 lbs. w/o driver; 3.55 gears with T5z (.62 5th); 91 5.0L short block, AFR165, ported Explorer intake, 65mm t/b, 75mm maf, 24# injectors, custom cam (mild duration, lots of lift and ramp rate); 1 5/8" shorties with dual 2.5" exhaust. Routinely got 17-18 in the city and 25-26 on the highway. Best tank of interstate only, really working at it was 28.7 mpg. Just got through swapping in an LS3 --- looks like it's going to do about the same as the 5.0L - with 100 more HP/lb-ft.

Note the comment further up about the 94/5 having a slightly longer input shaft and needing the bellhousing that matches the input shaft length....

You could ---- but why would you? You'd end up with something that 1) costs more to mod, 2) is heavier, 3) requires more cutting 4) isn't as quick and 5) handles/stops worse than if you went with a similar displacement pushrod smallblock. So - you could go Lincoln Navigator -- I suppose you could also put a Duramax diesel in one if you wanted to. And let's not forget the 8" cowl it's gonna take to clear the 5.4L - likely even the cam covers would be above the fenderline..... So - why would you want to do that Randy? There's creative and then there's just choosing poorly...

The real question is why cut it up to fit a motor that is longer, wider, taller and just as heavy (5.4 is heavier) than what you can build with an 8.2" deck pushrod motor? In most cases, you'll end up with something that costs more to modify, has less displacement and is bigger. That's why you don't see many. Unless of course you just want something different --- in which case, go for it.

Whatever valve train parts that let the 302 rev will also let the 347 rev. My brother's shop preps the racing 347 in a Shelby 350 replica that's a vintage racer. It sees 7500-8300 rpm on a regular basis without incident. The key for either one is a Dart or other aftermarket block as the stock 5.0L blocks are thin walled castings that will be splitting right down the lifter valley under that kind of stress. And most folks that are gonna spin a 351-based motor up there or higher will be using smaller rods and cutting down the crank rod journals to a Cleveland-size 2.75" or smaller so that oil shear at high rpm with the 3" bearings isn't a problem. Of course -- you don't need lots of revs to make lots of power with these. A well built stroker (Dart based) with 340-360 cubes and 10-15 psi of boost is more than capable of turning out 600-800 HP all below 6500 rpm.

The R/S ratio with a competently built 347 isn't any worse than a 427/454 Chevy big block. If you've been to the track lately around well built strokers based on the 8.2" short deck block - you'd see that the r/s ratio and rod length on the baby strokers doesn't limit rev-ability at all. All the noise about rod angles and cylinder wear is simply a non-issue in a properly built motor with quality machining and parts. As for the aftermarket block weighing more - it does. Nevertheless, the difference between the 8.2" block and the 9.5" block is significant. You needn't speculate -- check out shipping weights from various crate engine manufacturers and you'll get an idea of the difference. It's more than 50 lbs. with the rotating assembly - and you have to account for the rotating assembly. And the 3" mains that the 351 comes with result in a crank that weighs more (rotational weight increase is a parasitic loss) and cause oil shear issues at high rpm. The really hi-po 351's are set up to run smaller mains to solve that issue. Keep in mind - the original poster's question was 347 vs. 351. If that's the question, and similar parts are used - the 347 is going to outperform the 351. If we're talking about getting the most output one can regardless of weight/size of the block/etc. -- sure, other options will prevail.

The biggest bore you can get for the 8.2" Windsor small block from Dart is 4.125" -- with ultrasonic checking to be sure the wall thickness is there, you should be able to take it .060" over to 4.185". I'm pretty sure that's max. Bore spacing on the 351 (9.5") is the same; you have to go up to a 10.2" big block to get larger than that.

If possible, you want to get rid of those heads (E6's) and get a pair of E7's from an 87-95 motor (Stang), or better yet, hit your local pick/pull and get a set of GT40/GT40P irons from an Explorer or Mountaineer. The GT40's came on 96 and very early 97's; the GT40P's came on the rest of the 97's-01. Also, the 86 pistons have no valve reliefs (true flat tops) - so piston to valve clearance is a potential issue with almost any aftermarket camshaft --- if you change the heads (and you'll want to) - be sure to measure p to v clearance. The T5 transmission out of any 85-95 V8 Stang is what you want. Don't get the 4-cylinder version. And if you're willing to buy new (most used T5's behind the V8's are long in tooth, no pun) get the T5-Z which has the first 4 gears a bit closer in ratio and 5th gear more overdriven. The stock T5 is 3.35, 1.94, 1.29, 1.00, .675; the T5-Z is 2.95, 1.94, 1.34, 1.00, .625.

?? As I recall, the bore center spacing on the Windsor blocks (221" - 351" W) is only 4.38" -- so there'd be no way to get a 4.4" bore out of them....??

Based on the mod motor - longer, taller, wider, heavier than the pushrod distant cousins -- with care, you can build more power, lots more torque down low for much less money. Unless you just have to have ohcams and multi-valves - and if that's the case, keep it in the family and drop an Infiniti V8 in...

Dart block (aluminum if you'd really like to have fun) - 4.185" bore (.060" over on the 4.125" block) X 3.400" bore = 374 cubic inches. The big bore unshrouds the intake valve and with quality components a 6500-7000 rpm screamer is relatively easy to put together. 450-500 crank HP without too much drama. Just goes to show - there is no substitute for cubic DOLLARS.

Bigger weight difference than that when both are equipped with heads/intake/exhaust manifolds out of the same material. The 351 (9.5" deck height) weighs 75-100 lbs. more than the 302-based 347 (8.2" deck height). With very similar bore/stroke - if they're built to a similar level of tune, output will be similar - but you'll be carrying around more weight with the 351, and it's harder to fit under stock hoods. Also, the rotating assembly weighs more and the 3" mains in the 351 are prone to oiling issues if you really want to turn high rpm - both those issues give the edge to the 347. Those serious about rpm fit them with smaller main journals. Of course, the 351 can be stroked up into the 430 cubic inch range - and then the game is over in terms of comparisons. Lastly - the 351 blocks are stronger than the stock late model thin-walled casting 5.0L motors. The 5.0's are great for a mild street/strip build, but if you're going to add boost, juice or rpm (lots of time above say 6200-6500 rpm) you'd best start with an aftermarket Dart block because the stockers are notorious for splitting right through the lifter valley when really pushed. With the big bore Dart block and custom rods pistons you can build up into the 370 cubic inch range on an 8.2" deck -- it'll look just like the old 260 from 1964 --- but act like a 400 cubic inch small block.

An 89 notch fox body with few options weighs more like 2950-3000. The heavily optioned verts near the 3300-3400 range.

One of the fox body intake gurus up in St. Louis - Tom Moss; 87 speed density fox body. GT40P cast iron heads, Explorer intake (ported lower), exhaust, 65mm Explorer throttle body, stock HO cam, 1.7 rollers - 277 rwhp, 330 rwlb-ft. Idles like stock, routinely gets 18-20 mpg around town, 25-27 mpg on the highway. So, it can work -- but mass air offers more flexibility.

It's relatively straightforward to build up to 430 (or so) cubes starting with the 9.5" Windsor block (351) and adding the stroker kit. Power levels are comparable with the old big blocks; parts are less expensive; and the motor is much lighter when equipped with similar materials for heads, intake, etc. Not sure why anyone would want to go with one of the old school big blocks unless you just like 'em. And if you do - go for it.

The mod motor is longer, wider, taller and heavier than an 8.2" pushrod motor with aluminum heads. No much reason to ever use one in an application like this unless you just want something different. The cast iron block/supercharged Cobra mod motor is heavier, longer, taller and wider than a 460 Ford! Mod parts are more expensive.....I'd go GM LS long before I'd consider the mod motor; and if I just wanted something different, I'd drop a turbo-Supra 6 in....

Actually the E is just as bad as the B. While it has less duration, if you look at the valve events and lobe separation it causes some of the same issues. Most folks are lucky to get 11-14" of vacuum at idle. I had to move my idle up to 1100 rpm to get to 12" of vacuum. Bottom end is killed in most combos and with speed density, that vacuum level throws everything off. The CompCams XE258 will work pretty well, as will the cam many refer to as the 'baby Crower'. Both are sort of like the stock HO cam on steroids. But it's pretty easy to make in the 280/330 hp/torque range with the stock cam and a careful selection of complimentary parts -- so, no reason to try and squeeze and aftermarket cam past the SD's stock tables. Just to finalize the thought - SIGNIFICANT air flow changes can be handled by the SD ecu (180HP stock at the wheels to 280 at the wheels represents over 50% increase in air flow); it's the vacuum signal being reduced at idle/low rpm that really mucks things up since the system pays so much attention to the MAP sensor.

?Can't seem to get a signature line to show up.....? Ah, guess that solved it.

The 85-95 Stangs were all HO (and roller) 5.0's. 85's were carbed; 86-88 were speed density sefi; 89-95 mass air sefi. The exception were 88 CA cars - they were mass air cars. As others mentioned -- other good candidates for roller/HO motors are the Lincoln MkViii, the later model T'birds and Cougars with the 5.0 motors, and perhaps best of all, the Explorer and Mountaineer motors. The SUV motors were roller motors and also had the GT40 (96/early 97) or GT40P (97-01) heads and GT40 intake --- MUCH better than the stock HO E7 heads and HO intake. The camshaft has to go unless you want to shift at 4500 rpm -- but most of you are going to change out the camshaft anyhow. Also, the 86 Stang had flat tops with no valve reliefs and an E6 head which is a real dog compared to the E7 -- so generally, that's a year you want to stay away from. If you search around, you'll also find roller motors in various Crown vics, full size Mercury sedans, F150 trucks and Lincoln Town cars - but head, intake and cam choice mean that for a performance application most of these are gonna be useful primarily for the shortblock. Explorer/Mountaineer is the hot set up -- especially if you want to go with the distributorless ignition that these vehicles came with. 93-95 Mustang Cobras also came with 5.0L roller motor with GT40 heads and the Cobra intake. The Explorer/Mountaineer/Cobra/GT40 tubular intakes all share the same lower intake and it's the bottleneck to flow (about 210 cfm per runner stock) - so they all perform the same. The tubular upper weighs several pounds less than the other cast upper options. Having someone who knows what they're doing port the GT40 lower (Tom Moss - St. Louis, Missouri), adding a decent exhaust system, a set of AFR165 aluminum heads, 24 lb/hr injectors and a matching maf (75mm), a 65mm throttle body (you can use the Explorer/Mountaineer with a bit of modding for the throttle cable attachment) and the stock HO cam will deliver a motor capable of about 300 rwhp, 330 rwtorque, idle at 700 rpm smoothly/quietly, and get a solid 20 mpg around town and 25-29 on the highway if you can control your right foot. BTW, if you're adding boost - the switch to Hypereutectic pistons was made in late 92 - so some 92's have the hypers. 91 and earlier have the forged units. The only way to be sure is to pull the pan and look for the TRW logo on the bottom of the forged units - you cannot tell from the exterior or the top of the piston. Also if adding boost - the stock thinwalled castings aren't the strongest in the world. With time at extended rpm (say above 6500), when HP/torque start to reach into the 450 range or if detonation continues unabated for long periods of time, the stock blocks are know quite often to split right through the middle of the lifter valley. So if you're gonna boost or juice - best to start with a Dart block. Or go GM/LS-1/2/3..... Lastly, the speed density cars will actually tolerate mild changes quite well. There are a number with GT40P heads, carefully ported Explorer intakes, 65mm throttle bodies, decent exhaust system, upgraded fuel pumps and pressure (for more fuel to go with more air) and stock HO cams that put down in the 250-280HP range, and 300-330 torque range all at the wheels. The key is to not go crazy with cam choice -- anything that significantly alters the vacuum signal at idle (18-20" stock) is gonna give the stock speed density ecu fits. http://forums.corral.net/photopost/showphoto.php?photo=55168&ppuser=30684