408 build morphing to 427.... Any thoughts?

[Ourobos]

I totally agree with you !! my 408 build (which I designed and put together myself other then block prep) while running large heads and a fairly aggressive solid roller loves the 3200 stall behind it. that being said even with that amount of stall it will pull the idle down a few hundred when in gear and you can still ease the eb around. cruises the highway at 2600 no problem but yet out of the hole or anytime you flash it the motor builds enough torque to flash 3200+ (dyno showed nearly 500 ft at 3000) . for Tyla I would say any stall from 2500-3500rpm they will be happy with. about the only drawback I've found with a high stall off roading is steep downhill decents they will freewheel to a point(not a lot but noticeable)but I love how I can dial torque to the tires by gradually loading the converter or flash it and blow the tires loose. I also agree the rpm airgap will probably be somewhat of a bottleneck, it will help the bottom end but not much while hindering mid and top, the vic jr port matched will out perform it everywhere from 2500 and up and if he runs a 2500 or higher stall the airgap is a mute point. from block to the last screw on my build I came in right around 7k$ but would have been close to that 10k mark if I didn't have good friends in the industry. got bargains on my block, crank, cam, heads etc.

Funny, the Victor Jr. is exactly what I had in mind too.

 

[Tyla's toy]

I would agree this is a build for a guy I met through wh when I was ordering some parts. Monday I'm going to tweak with Keith craft and they say end of January at my door. Plusi want fuel injection

 

[Tyla's toy]

Don't forget headers, you cannot run a 1 1/2 primary and expect 500hp.

Talked to the engine builder today specifically about exhaust and the the Dyno used for the tests above has 1 5/8" headers. They also said they find more power loss with air cleaner choice than header. A larger header would impact the hp but hurt tq in their opinion.

 

[Tyla's toy]

Funny, the Victor Jr. is exactly what I had in mind too.

I called today and asked specifically about the victor jr and they do much better in the lower rpm scale with the air gap. He said he would consider Vic jar if it were a race car but would strongly vote against it in a 4wd.

I love all the input because it gives me questions to ask and opportunity to learn!

 

[Letsgocrawling]

I'm running a super victor and I have no hesitation whats so ever. The 408 makes gobs of tourque anywhere you want it---off idle to full throttle. There are simularitys with your choice and my deal. Just my 2 cents
mark

 

[Tyla's toy]

I'm running a super victor and I have no hesitation whats so ever. The 408 makes gobs of tourque anywhere you want it---off idle to full throttle. There are simularitys with your choice and my deal. Just my 2 cents
mark

I would agree when you get up into these numbers there's more than enough sack. I'm just following up on suggestions and reporting feedback from the builder. I personally don't have the experience to make these calls on my own so I keep grinding and researching and all with an open mind. I'm glad to have the contributions that's for sure!

 

[74strokerbronco]

I have engine analyzer pro and it's pretty accurate and like I said before from 2000 rpm and up the vic jr makes more hp and more torque then the air gap and at 5k it's ahead 15 ft and 20hp over a air gap on a 408 and if you plan on a stall converter of 2500rpm or better there is no benefit at all to the air gap, and I believe the vic jr is less or the same $$ I choose the vic jr over the super vic based on flow numbers and runner lengths. and with minor work on the long runners you can have the bottom end close to a air gap and the topend close to a super vic. you really have to think bigblock type flow with these larger strokers to get them to breath and make good power over a large rpm range my motor averages 536hp and 538 ft of torque from 3000-7500rpm with peak hp of 672@6700 and 601 ft @5100 and that's dyno proven. and this is done with larger heads and cam then your talking which should be hurting bottom end if you want to believe the little cam little heads make torque guys'

as far as headers 1 5/8 minimum and you will still be losing some of the motor potential I would go 1 3/4 primaries there wont be any loss of torque from 1500 rpm and up while giving a much stronger mid and topend

 

[Ourobos]

I'm running a super victor and I have no hesitation whats so ever. The 408 makes gobs of tourque anywhere you want it---off idle to full throttle. There are simularitys with your choice and my deal. Just my 2 cents
mark

This X2.....

 

[Letsgocrawling]

I have engine analyzer pro and it's pretty accurate and like I said before from 2000 rpm and up the vic jr makes more hp and more torque then the air gap and at 5k it's ahead 15 ft and 20hp over a air gap on a 408 and if you plan on a stall converter of 2500rpm or better there is no benefit at all to the air gap, and I believe the vic jr is less or the same $$ I choose the vic jr over the super vic based on flow numbers and runner lengths. and with minor work on the long runners you can have the bottom end close to a air gap and the topend close to a super vic. you really have to think bigblock type flow with these larger strokers to get them to breath and make good power over a large rpm range my motor averages 536hp and 538 ft of torque from 3000-7500rpm with peak hp of 672@6700 and 601 ft @5100 and that's dyno proven. and this is done with larger heads and cam then your talking which should be hurting bottom end if you want to believe the little cam little heads make torque guys'

as far as headers 1 5/8 minimum and you will still be losing some of the motor potential I would go 1 3/4 primaries there wont be any loss of torque from 1500 rpm and up while giving a much stronger mid and topend

Why would you want to do any porting or anything like that, I did'nt, you do'nt have to touch the stuff, component compatability is where it's at. My combination did'nt even require me to port match anything. The stuff lined up perfectly. There was a little luck on my side, granted---mismatch of parts are the biggest headache engine builders deal with. Engine---power build software is soft, only a baseline, real results come from experienced builders who have creditable proof of there achievments. 1.75 primarys work great for my combo, but then I went with tri ys also, so there is a comprimise! Look forward to seeing Tyla's progress.
mark

 

[Letsgocrawling]

Guys, had to follow with this---that's why my sh---ts sticks out of th hood, ugh, but until I HAVE ANOTHER EB---I'LL LIVE WITH IT!
mark

 

[74strokerbronco]

Why would you want to do any porting or anything like that, I did'nt, you do'nt have to touch the stuff, component compatability is where it's at. My combination did'nt even require me to port match anything. The stuff lined up perfectly. There was a little luck on my side, granted---mismatch of parts are the biggest headache engine builders deal with. Engine---power build software is soft, only a baseline, real results come from experienced builders who have creditable proof of there achievments. 1.75 primarys work great for my combo, but then I went with tri ys also, so there is a comprimise! Look forward to seeing Tyla's progress.
mark

why would I want to port ?? wow ok why would anyone send there heads and intakes to places like tea/foxlake/spiers racing etc etc because most stuff out of box can be improved on, I even see where you say your tfr's are worked over by tea. I didn't port to fix mismatched parts etc and I didn't say port matched , I ported the long runners so that all 8 cylinders have similar flow . with heads flowing over 340 cfm at .700 why would I want long runners that only flow 301-310 out of box form feeding intake ports that need 340+ duh !! after porting the long runners and cleaning up the short ones my vic jr flow 345-355 across all 8 runners my motor speaks for itself, see you at the dunes I hope !! As far as software being soft I agree but it's still a tool and a good one at that and is great for baseline info.

 

[74strokerbronco]

Look I came to tyla's thread to give my imput and related knowledge and experience to help the op make informed decisions. I gave my opinion why I believe the vic jr is a better choice over a air gap. the op can use that info or disregard it. I will note that letsgocrawlings tfr box intake has all equal length runners and thus does not require the extra work to get balanced flow to each cylinder that traditional single carburator intakes like the air gap or victors benefit from. to the op keith craft gets all there heads more or less bare and run there own cnc porting program on them and there good programs.

 

[Tyla's toy]

Thanks for all the input it's of tremendous value!

 

[Monster Mike]

great thread, subscribed

 

[Tyla's toy]

Look I came to tyla's thread to give my imput and related knowledge and experience to help the op make informed decisions. I gave my opinion why I believe the vic jr is a better choice over a air gap. the op can use that info or disregard it. I will note that letsgocrawlings tfr box intake has all equal length runners and thus does not require the extra work to get balanced flow to each cylinder that traditional single carburator intakes like the air gap or victors benefit from. to the op keith craft gets all there heads more or less bare and run there own cnc porting program on them and there good programs.

From Keith craft:

I have dyno tested engines back to back and there is not that much difference. It may make a little more but it is higher in the rpm range and not really what we would be looking for here. I can build the engine with a Victor Jr and using the higher stall but I know from past feedback that you will more than likely dislike like it. We use that combo for light weight cars that want a harder launch. If you are looking for the larger hp and torque number we can use an AFR 205 and the Victor Jr but the low end will suffer. I will build it anyway you like just trying to let you know what we have found to work well. Thanks

 

[eb-nutt1]

All reasons why some of us build on the Cleveland foundation instead...which can be taken all the way out to about 466 ci or so..

I am very impressed with some of the numbers I've seen more recently, and in this thread, for 408W builds though. Way better than my decade old 408C build. I'm going to rectify that soon, though.

Hey BMC--not every tom, dick, or harry as a secret stash of 400m blocks to work with! You know i've been around cars/trks and especially fords for over 30 years and can count on both hands the number of factory equipped 400m motored vehicles i've encountered during this time. Most be a northern thing with all those motors?

Brian

 

[74strokerbronco]

Tyla ultimately it's your build and your choices just trying to help. keith has alot ALOT of motors out there and a lot of practical experience and feedback. it's kinda like he said , I personally enjoy the harder hit/launch but I really don't care to much about easy streetability. it's really a matter of how you want YOUR motor to behave and how much power/torque you want and where you want it. what ever you want I'm certain keiths crew will get it for you . let us all know what you finally settle on

 

[97XEB]

So, the 408 that came in my Bronco when I bought it used was supposedly built back in the day by Kuntz & Craft. (I have what is supposedly the build sheet.)

Not sure what changed before I got her, but when she came to me, she had the Edelbrock Vic Jr single plane intake and an Edelbrock Performer carb. Without a doubt, my Bronco was THE FASTEST VEHICLE I had ever driven in my life, and I've driven some pretty fast cars.

However, she wouldn't run on the trails. Hated hills - up or down - hated bouncing around, hated off-camber angles, hated idling and hated slow speed putting around. Constantly sputtered & stalled.

Since I wanted a trail rig more than a drag racer and knowing I had gobs of power to play with, I replaced the Edelbrock stuff with a Weiand Stealth dual plane intake and a Holley Truck Avenger. I definitely lost some top end power, but she runs much better on the trails, does everything I want her to do - and still tons of power. (People are surprised when I tell them it's not fuel injected.)

Maybe I could have left the Vic Jr, but but from what I read and the people I talked to, I was told a dual plane intake is better for a 4x4 that will be used on the trails than the wide open single plane. In truth, the Weiand Stealth is not much shorter then the hi-rise Vic Jr so maybe with some porting and polishing the Stealth could flow similar to the Vic Jr?

See what Keith says about the Weiand Stealth, is that a good intake option for you?

Either way, congrats on the 408 build. You will love it.

 

[airbur]

I just realized you aren't going EFI? This awesome build needs EFI man.

 

[bmc69]

Hey BMC--not every tom, dick, or harry as a secret stash of 400m blocks to work with!

Well..my stash of 400 parts isn't really a secret... And I'm down to only 6 or 8, so the supply is dwindling.

I'm still going to get around to building one to 460 ci....sooner or later.


The current 408C I'm building to go in the '78 Bronc is only going to be about 380HP and 475 ft-lbs..so not in the same league as the motor under discussion here. It is MPFI though...