New engine combo ideas

[1slow95]

I've been wanting something different for a while now, and since my engine's broke it's the perfect time for a change. Here's what I want:

#1 Much improved driveability (like stock)
#2 More power

Those two don't really go together NA, so I'm thinking a single turbo setup is the way to go. Here's what I have in mind.

351W, stock crank, H beam rods, forged pistons, 9:1 compression. Re-use my current top end, AFR 225 heads and Vic 5.8 intake. Mild cam from FTI. I'm not sure what turbo to go with, but the S400 seems to be a popular choice.

I know this setup will make ridiculous power with boost, but I'm not sure how it will behave NA. I can't afford this all at once so I just want to get it running this winter, then work on the turbo next winter. My main concern is how much low end torque it'll make with the huge heads and intake. I don't need 350+rwtq at 2000 rpm like my current setup made, but I don't want it to be a dog off the line either.

Any suggestions/comments? Is 9:1 too much compression for pump gas? Should I go with a small stroker kit instead of the stock 351? I'm on a tight budget, and my HP goal is only 500rwhp for now so I don't need a huge 427 stroker or anything like that. After a fuel system upgrade I'll go for 650+rwhp, but 351ci should still be plenty big enough to reach that goal.

 

[BlackVert]

that sounds like a great plan to me. with 351 cubes and a 9:1 CR, i bet you will still be able to spin the tires pretty easily. and it will also be good for low octane pump gas. i'd probably get something with longer runners so the bottom end wouldn't be too soft. with the turbo kicking in at the upper ranges, the long runners shouldn't hurt you there either.

as to the turbo, that depends on when you want it to kick in. personally, since i'd want to be able to drive it anywhere and everywhere, i'd want something that would be docile in light throttle/cruising speeds, and have it kick in with a vengeance around 3000 rpm. so i'd want a pretty big snail that didn't spool up immediately. that way, gas mileage could still be good if i could stay off the throttle.

 

[nmcgrawj]

I dont think you'll need a stroker with a turbo to get to the max hp levels of the block. So i would save money there.


Also, what do you consider soft downlow? I imagine there's a difference between soft for a 302, 351, and a 418 LOL Would you be happy with what healthy 302's do in the low rpms?


Most importantly, what does Ed say to expect with those heads and "only" 351w cubes?

 

[1slow95]

I went from a stock 302 to a built 418 so I don't have any experience with anything in between. I'm thinking around 250-280rwtq at 2000-2500 rpm should be fine. Stock made 240 at 2500 so I would think a 351 should be able to top that.

My reason for keeping my intake is to keep costs down. Plus it should be awesome for boost. Also, I like the short runner design because it clears my valve covers easily, which also now have coil packs mounted on them so I need even more clearance.

I haven't got in touch with Ed yet. Still doing some research to make sure this is the way I want to go....Plus I don't have the money for a cam yet, need to get my heads fixed first.

 

[nmcgrawj]

I don't think you need to worry about torque and downgrading to a long runner intake with the 351. If turbo 302s run holley systemax intakes....you'll be fine. And still, the cam can make it or break it!

If I were you I'd email Ed to let him know what happened....where you wanna go(or think u wanna go) and how u think you can get there. I know you don't have money to trade in your cam yet....but you already paid Ed for your his advice and guidance. Which will help u find your way. I always get email responses from him first thing in the morning....he probably replies before he gets busy at the shop.


My guess is he will probably say something like "fix the heads, trade in your cam and run it. It'll purr like a kitten."

lol his emails are always so short n straight to the point. Yet he always delivers!

 

[revhead347]

That sounds like an awesome plan. Is that crank from your 418rwhp toast? It wouldn't hurt to keep the cubic inches. I would go for 8.5:1. 9:1 will work ok, but the lower compression will make it more street friendly.

Kurt

 

[1slow95]

I haven't got to the bottom end yet, but as far as I can tell I could probably get away with just a new piston, rings, and bearings and have it back to the way it was before it broke. There's a couple problems I've found with using my 418 and a turbo....One is my heads have 58cc chambers so it'll be hard to get the compression down... Second, it'll make way more power than I'm looking for.....but I guess that's not really a bad thing ....And third my block is already .040 over and needs to go .060 over to clean it up properly. It was like than when I built it and it ran fine, but I don't know if I'd trust it with boost. I'm thinking I'll try to find a newer roller block 351 and use it.

 

[S351Saleen77]

Sorry to hear about your engine. I haven't been on here too much lately.

On your intake there is no provision for the PCV is there?? I am thinking of a new intake to replace the Saleen modified one on #58.
The TFS R is the other intake I'm thinking of.

 

[1slow95]

Yep, there's no PCV on my intake. You could run it from one of the valve covers if you need to.

 

[nmcgrawj]

I assumed you were sticking with the older block....be careful with those high HP levels on a roller block!



You could just run less boost if u kept all the cubes...u could even probably just toss in a stock cam, maybe retard it a bit. Only thing i can imagine being worse with more cubes is your MPG during part throttle.

 

[1slow95]

Well it's either run my block .060 over or get a new block. I like the 1 piece rear main seal on the new blocks, I think my 2 piece seal has been leaking. I don't plan on running more than 650-700rwhp, and I don't plan on revving it much past 6000. I have an AEM so I should be able to get a good safe tune on it, plus I can install a knock sensor if I want to.

I'll do some more research on it before I decide anything though.

 

[revhead347]

I would get a roller block, 700rwhp with a turbo shouldn't be any issue at all. I think you'll be fine reusing your crank and rods on a new block. I gather you can do a .030" over block and it will be something like 408cid. Not sure exactly what you're stroke is. Reusing the parts you have almost always saves money. They make pistons to get the compression down, that won't be an issue. Having a longer stroke isn't actually going to make the engine produce a whole lot more power. It's actually going to help you by moving the power down to a lower rpm. RPM kills an engine more than anything.

Kurt

 

[1slow95]

I'll need something in the range of 40cc dished pistons to bring my cr down to 9:1 if I keep my 418 crank and rods. Mine are 22cc and I haven't found much more than that available. It looks like I need different heads, or have my combustion chambers opened up, for a stroker to work with boost.

My engine specs:
4.040 bore
4.100 stroke
6.200 rod length
= 420 ci

4.030 = 418, 4.020 = 416, 4.010 = 414, 4.000 = 412

 

[nmcgrawj]

Are you gonna be ok if that 650-700rwhp breaks a roller block?


You "should" be ok as some people say, while others wouldnt agree. I feel like with that much power why not play it safe? ( i know the obvious answer is $$$$$) But still, if the block lets go....how bad is it gonna hurt you financially?


Unless i knew building another shortblock wasnt an issue financially....if i was building a 700rwhp setup i would just hold out for a block i knew could handle it with ease. I wouldnt put much faith into a block that is gonna be operating in the "grey area" of its HP capability.

It would suck that a "shouldnt be a problem" turns into a problem, then u figure out you are out more than the cost of a dart block or something by the time u get it back on the road.



Just food for thought....thats gonna be a bad bitch with that much HP!

 

[BlackVert]

how about getting a running roller 351, swapping your intake over to it and strapping your turbo on that?

the weak link there would be the pistons, but if the tune is safe, they would hold up.

seems to me that'd be a very cost effective approach. and the stock cam is good for drivability and boost because there is no valve timing overlap.

or take it apart and upgrade the pistons (and rods too if necessary)

heads are less of a restriction when the air is being forced through them

or you could sell the 225s and use that money to buy heads with larger chambers.

 

[revhead347]

Getting different heads really doesn't change the compression ratio that much. The biggest heads are usually around 65cc, which is only 7cc more than you have now. The pistons are -20cc already. You may not find any advertised pistons with that much dish, but you will be surprised what's available when you call the manufacturer. Most manufactures don't waste advertising space on pistons they don't sell very often. The best way to do it is to get a Man O War block with the taller 9.7" deck height, but I can understand that's a huge financial burden.

750rwhp on a turbo roller block isn't even an issue. I wouldn't be concerned until the engine starts putting over 1000 to the wheels. If it comes apart, it's going to be some other issue other than the strength of the block. So the only difference with going with a better block, is that when it comes apart, you've ruined a more expensive block.

Kurt

 

[nmcgrawj]

Getting different heads really doesn't change the compression ratio that much. The biggest heads are usually around 65cc, which is only 7cc more than you have now. The pistons are -20cc already. You may not find any advertised pistons with that much dish, but you will be surprised what's available when you call the manufacturer. Most manufactures don't waste advertising space on pistons they don't sell very often. The best way to do it is to get a Man O War block with the taller 9.7" deck height, but I can understand that's a huge financial burden.

750rwhp on a turbo roller block isn't even an issue. I wouldn't be concerned until the engine starts putting over 1000 to the wheels. If it comes apart, it's going to be some other issue other than the strength of the block. So the only difference with going with a better block, is that when it comes apart, you've ruined a more expensive block.

Kurt

1,000HP on a stock roller 351 block?


How high do u claim a factory 302 block can go?


And most of all, i'm sure u can fire an engine up with that much HP....but how long is it going to last? A summer?



Gotta say Kurt....i've never heard of 1,000hp and factory block mentioned in the same sentence unless it was to upgrade to a better block. Got any more info, links, proof, etc? Dont want guys to come in here thinking they can do it and blow it to pieces and not have the $$$$ to rebuild.

 

[revhead347]

I've been running my stock 302 block at 500rwhp for about 10 years. There are two guys in Texas with 900rwhp turbo 5.0s with stock blocks. One of them is black, you can find video of it on the internet. The stock block isn't as strong as the aftermarket blocks, but the weaknesses are overated. Most of the stock blocks that crack are from other problems in the engine, and everyone just assumes it was a block problem. You can do some youtube and google research, you are going to find some pretty stout 351 blocks out there. I wouldn't go crazy trying to make power with nitrous, but the turbo is a much more effective way to make power, and you can push it a little more. RPM kills a block faster than anything, not net power. Turbo engines make more power down low where the rpm isn't walking the caps as much. That's why I thought it was a better idea to stick with the 4.10" stroke crank, where you can make peak power at 5000rpms or lower.

When you are talking about engines, start thinking about the processes that go on inside the engine, instead of making assumptions based on very raw data. Most of the people who are just getting themself into the Mustang game aren't building 1000rwhp cars as soon as they join a website. Low 5.0 clearly has quite a bit of experience, and he knows that all race engines carry some risk.

Kurt

 

[nmcgrawj]

I've been running my stock 302 block at 500rwhp for about 10 years. There are two guys in Texas with 900rwhp turbo 5.0s with stock blocks. One of them is black, you can find video of it on the internet. The stock block isn't as strong as the aftermarket blocks, but the weaknesses are overated. Most of the stock blocks that crack are from other problems in the engine, and everyone just assumes it was a block problem. You can do some youtube and google research, you are going to find some pretty stout 351 blocks out there. I wouldn't go crazy trying to make power with nitrous, but the turbo is a much more effective way to make power, and you can push it a little more. RPM kills a block faster than anything, not net power. Turbo engines make more power down low where the rpm isn't walking the caps as much. That's why I thought it was a better idea to stick with the 4.10" stroke crank, where you can make peak power at 5000rpms or lower.

When you are talking about engines, start thinking about the processes that go on inside the engine, instead of making assumptions based on very raw data. Most of the people who are just getting themself into the Mustang game aren't building 1000rwhp cars as soon as they join a website. Low 5.0 clearly has quite a bit of experience, and he knows that all race engines carry some risk.

Kurt

Interesting stuff.

 

[1slow95]

Yeah looking on turbomustangs.com, most of the 351 block failures are from the main caps walking. I can add a main girdle, but I'm not real sure if it helps or not. I found one guy on there running 8's with a stock block and crank! Another guy there told me that anything below 1000 hp is "relatively low power".

What I would really like to do is a Boss 331, but that's way more money than I want to spend. I'd have to re-buy several parts to downgrade from the 351 to 302, plus the block is $1500+. I already have everything for the 351 and the general consensus is that the 351 block is stronger than the stock 302 so I think a stock block 351 is my best option.