351w upgrades

[afterglow]

I recently restored a 69 fastback with the following:

'74 351w
Holley Street Avenger 670cfm
Weiand Stealth
Compcams XE262H
C6
MSD6A
Hookers (1-5/8")
Magnaflow exhaust (2.5")
8-inch 3.8 Truetrac

I'm looking to upgrade the engine but want to reuse what I have as much as possible since it's a pretty new restoration. I'd love to go with a stroker but that would be way out of budget since I'd have to upgrade tons of stuff. I'm thinking of upgrading heads, pistons, cam & carb and keep everything else. It would be great if I could reuse the cam and/or carb though.... The car has SFC's and upgraded suspension so it should handle more power easily. It's a pure weekend street car and is virtually never on the highway.

What would you recommend?? And what sort of hp/torque/1/4 mile numbers will I get with your recommendation??

 

[yeloxr7]

That's not a restoration, its a restomod or a street machine......

 

[SadbutTrue]

I recently restored a 69 fastback with the following:

'74 351w
Holley Street Avenger 670cfm
Weiand Stealth
Compcams XE262H
C6
MSD6A
Hookers (1-5/8")
Magnaflow exhaust (2.5")
8-inch 3.8 Truetrac

I'm looking to upgrade the engine but want to reuse what I have as much as possible since it's a pretty new restoration. I'd love to go with a stroker but that would be way out of budget since I'd have to upgrade tons of stuff. I'm thinking of upgrading heads, pistons, cam & carb and keep everything else. It would be great if I could reuse the cam and/or carb though.... The car has SFC's and upgraded suspension so it should handle more power easily. It's a pure weekend street car and is virtually never on the highway.

What would you recommend?? And what sort of hp/torque/1/4 mile numbers will I get with your recommendation??

Get some heads. AFRs, Trick Flows, Performer RPMs... whatever. You'll need a bunch of little things (new valve springs, pushrods, lifters, rockers, bolts, valve covers, etc), but its the logical next step.

C6s are kind of pigs, a nice used C4 might free up a little power and lose some weight. Won't be a huge difference, but shouldn't be too expensive either.

A 9" rear wouldnt' be a bad idea either, but might not be necessary.

The parts you have now are fine though, no reason to change your cam, intake, carb, exhaust... they should all work well.

With a head swap, depending on the heads you get, you could pick up 40-100 horses and probably run a mid to low 13 in street trim without going nuts removing weight and such at the track. You could probably hit 12s if you're a great driver and do some weight reduction and use slicks.

 

[rbohm]

i would drop on a set of performer rpm heads, and swap in an AOD. then i would go to 4 wheel disc brakes, and work on the rest of the chassis, like subframe connectors, lower the upper control arm pivot point(dazecars.com has a template and drill bit to accomplish this task). i would also upgrade the rest of the suspension as well. check out opentrackers website.

 

[danny clemens]

Change to a C4 or an AOD trans, 9" rear and different heads. Performer RPM's with the 2.02 intake valve or go a little more money and get the AFR 185s. You could go with a little more cam but you'd probably need a stall then.

 

[SadbutTrue]

Change to a C4 or an AOD trans, 9" rear and different heads. Performer RPM's with the 2.02 intake valve or go a little more money and get the AFR 185s. You could go with a little more cam but you'd probably need a stall then.

I'm gooood

 

[afterglow]

Thanks for the advice. I have front discs, subframe connectors, and all-new suspension including the Shelby drop and roller spring perches so I should be okay as far as brakes, chassis and suspension. The 8" I got was also rebuilt and has new Richmond gears and Detroit Truetrac. I should have gotten the 9" but didn't have the money back then.

I've been looking high and low for an AOD locally but living here in Asia sure makes it slim pickings. The C6 will have to do until I find something better.

Let's say I go for the Performer RPM heads. What other parts would I need to get??

 

[ratio411]

I'd love to go with a stroker but that would be way out of budget...

A 393 crank is dirt cheap when you figure in:
It uses stock rods (no money spent)
It uses 302 pistons (money saved)
And
You don't have to spend money on refurbishing your 351 crank (money saved)

It's almost like getting 42 cubes for free!
At 1 or more HP per cube, that's a steal!
Where else can you get that kind of HP cheap?
It's almost foolish not to do it.

 

[afterglow]

The stroker itself is easy enough but then I'd have to get a 9-inch and build it up. I've seen some 28-splines locally (all of them the wrong width) but the 31-splines are few and far between and importing one would be prohibitive.

 

[ratio411]

The stroker itself is easy enough but then I'd have to get a 9-inch and build it up. I've seen some 28-splines locally (all of them the wrong width) but the 31-splines are few and far between and importing one would be prohibitive.

I am honestly surprised your 8" has lasted behind a 351!
I have toasted 3 with 302s!
If your 8" hasn't gone out yet, you're lucky.
You are also pushing your luck by beefing up the 351...
So how is the 393 going to hurt you more?
Also, 31 spline axles are cool, but 28s aren't bad.

Why don't you get an undesireable (meaning cheap) 9" housing and put your 8" axle tubes and 28 spline axles on it? It was good enough for Shelby...
I don't know about welding shops where you are, but it runs around 200 bux here for the mod. Then all you need is a 28 spline chunk.

 

[Sicarius428]

Breaking the rear depends on traction. hehe. C6 is a pig but I would start with some heads to compliment the rest of your goods. As mentioned above Edelbrock, AFR and TFS are good companies.... it just depends on how much you want to spend. This way if you want to rebuild the shorblock for a stroker later on, you have the whole top end already.
Kevin

 

[ratio411]

So true...
You can't break an 8" with a C6 soaking up all your HP before it gets to the differential!

The ones I broke were behind C4s and a 4 speed.
No traction though...
I kept slapper bars to stop wheelhop, which is more detrimental to the rear than just spinning.

 

[afterglow]

Get some heads. AFRs, Trick Flows, Performer RPMs... whatever. You'll need a bunch of little things (new valve springs, pushrods, lifters, rockers, bolts, valve covers, etc), but its the logical next step.

Aside from the heads, what other things would I need to install them?? I got new lifters when I got my cam. I also have new valve covers that I haven't installed yet. What else do I need?

 

[Sicarius428]

Roller rockers would be nice since you are probably going to get some stud mounted rockers anyways.
Kevin

 

[Jester67]

I am honestly surprised your 8" has lasted behind a 351!
I have toasted 3 with 302s!
If your 8" hasn't gone out yet, you're lucky.
You are also pushing your luck by beefing up the 351...
So how is the 393 going to hurt you more?
Also, 31 spline axles are cool, but 28s aren't bad.

Why don't you get an undesireable (meaning cheap) 9" housing and put your 8" axle tubes and 28 spline axles on it? It was good enough for Shelby...
I don't know about welding shops where you are, but it runs around 200 bux here for the mod. Then all you need is a 28 spline chunk.

It’s not that surprising that the 8” has survived behind the 351 with an automatic. The C6 eats some HP and gives him a softer launch than a manual and he has not said what size tires he is using but I did not get the impression that he is running slicks so lack of traction will help it survive. Also I thought that the 74 and up motors where lower compression so he might not be getting that much performance from the 351 now.

 

[ratio411]

It’s not that surprising that the 8” has survived behind the 351 with an automatic...

Sounds like you haven't destroyed 4 of them yet!
3 of them I did with 302s...
2 of those with C4s...
All of them on street radials and no traction.

The 4th one I did behind a C6.
But I won't count that one because there was a 460 in front of the C6.