diehrd

I follow Straub on face book he is skilled for sure. Next motor he will be my cam man ....

I would happily pull up to you at a light , and when it turns green that additional torque on a street tire most likely will hurt you more then benefit you.

And that goes for most older style rear drive cars on a street tire. Once you close in or cross 500hp and tq it is now a challenge of getting that power to the pavement and street pavement is no friend of that kind of power.

496 BBC 71 chevelle .. Light to light I made him a laughing stock in our circle, dude hates me for it ... Keeps saying lets do a full quarter mile .. Why would I ... I even bought a custom license plate just for him ... UHAVLOST . . . . .

cardo0

Some day when u really want to hook u will look at big slicks that are much harder to spin. They hook so well they need to be literally screwed into the rim and run innertubes. Once your car hooks up the extra torque will be put to work and lower the 1/4 time. But if u dont drag race and road race instead then the higher rpm power would be favored.

Its all in the combination. The engine, trans, rear gears, tires, springs & shocks all need to be tuned for the kind of driving u do.

Enjoy what u have and dont worry what others say. Be happy u have something u finished to drive. There's plenty of others with a expensive engine that they cant make run because they got way ahead of themselves. U finished and drive what u wanted to do and thats whats important. Theres always the "next" engine for changes.

congratulations

bluedawg

I think your comparing apples to oranges comparing your heads to the lt1 heads, the Lt1 heads have a different port design and flow a lot more, they're the precursor to the Ls heads which flow really well and I'm not for sure about the lt1 heads but the Ls heads don't share the conventional 23 degree valve angle.

gkull

if you keep all your other parts and keep the compression the same using a 383 or 396 internals............ You would be amazed. I did some other changes including a 4.11............ but i went from a 12+ bracket racer to a 11.70 car.

TQ is a direct function of CI and it is at every rpm.

Then I jumped to a 427 and then bored to a 434.

I would not waste money on baby steps again. I would go right to the 441 - 472 ci SBC's or cheaper to just run a blow through supercharger

diehrd

Your making a mistake .. LT heads and my fast burns are similar the fast burn out flows the LT heads..

The LS head different platform no comparison

cardo0

The LT1 precursored the Vortec head but has an exceptional D shaped exh port that out flows the Vortec exh port. The D exh port is from the earlier L98 head - that and tight 58cc chambers. I really dont see anything related to the LS series heads.

bluedawg

I thought that the lt1 head was the precursor to the Ls head, the LT came out in 94 and the Ls came out in 2000. I might be thinking all wrong, its been known to happen, so back to the Googler for more research. the fast burn heads not a vortec right.

bluedawg

Why not a 472 with a procharger.

bluedawg

OK so the Vortec engine came out in 1985, the gen2 Lt1 engine came out in 1992 in the corvette and 1995 in the z28, the Gen 3 came out in 1997.

cardo0

U need to google L31 Vortec heads. They first came out in 1996. For some reason GM dropped the good flowing D exh port and changed the intake bolt pattern too. Cant speak for GM but that seems like steps backward.

diehrd

LT4 heads d port exhaust
vortec head exhaust not d port

Take the good from the LT heads and the vortec heads ,, and cast a aluminum fast burn head ... You end up with a D port exhaust and a tall intake runner 210

bluedawg

It does indeed seem like a step backward. When did the cathedral port heads come?

cardo0

All i know of the "fast burn" heads is they surprised everyone with the large vol 210cc intake runners and were then sold as 350" head. Now they put them on everything. Dont know what took GM so long to put them on the ZZ4 block to make the ZZ5. Maybe it was marketing as the base ZZ383 sells for less than the base ZZ5 does now. Those are both mild compression motors without good quench. Man if u can find good machine work and build a good short block with over 10:1 compression and good quench a larger cam it should make a real animal with those heads.

cardo0

First i heard of the cathedral port was the early stock LS heads. The fast burn head intake ports are taller than most GEN I heads but i never heard of a special intake for the fast burn heads so the difference is in my eyeballs i guess.

bluedawg

I remember the flow on the fast burn heads isn't bad but not as good as some of the top tier heads, especially given the 210cc runner and I'd always figured it was due to the size of the intake valve, if you increased the diameter of the intake valve and opened up the pocket to support the new diameter it would compared with the high end heads, most of the 210cc runner heads out their sport a 2.05" to 2.08" valve diameter. I was reading some thing a while back about valve diameter and piston diameter along with piston speed to dictate the speed of the intake charge and once that the intake charge velocity hit the speed of sound it wouldn't move any faster.

bluedawg

Google the ZZ5 and Google says that they use a 2.00" intake valve.

mvette76

this motor is not in a vette its a motor I built for my cousins 69 z/28 and the car is set up for drag racing it hooks really good and pulls like a freight train

scottyp99

Man, everybody always says that, "It pulls like a freight train!" You ever been on a freight train? They're pretty slow. I know, it's just an expression, I just think it's kinda funny, that's all.

Scott

diehrd

Remember we are talking a head made initially for a 350 and GM is quite a bit smarter in design then a lot of people want to admit.

That raised runner (210) and valve size are specifically combined to maintain velocity of the intake charge. I doubt making the pocket bigger and valves bigger would result in better performance on the fast burn. GM created the term fast burn not as a gimmick but because the design causes a fast burn of the mixture and allows for timing as low as 32 degrees all in where the "Top Tier" heads want 36 all in.

If bigger valves 2.08 and runners and pockets are used I think you would be better off using those heads on more cubic inches like a 406 and up. And to use them on a 350 would be a waste.

I am no engine builder but I am fairly well schooled on topics that interest me and I could find no head offering anything the fast burn does not provide when using a 350ci motor , in fact it is my opinion if you stick with 350 like I have the fast burn is a top tier choice all the way.

cardo0

Soo many good small block heads out there and soo many details its a 40 hr/wk job just to keep current with them all. Latest technique is to "wet flow" the heads. And some heads that boast wet flow technology dont have the highest "bench air flow" numbers. I cant answer for that. Can air flow be too much and wasted? It has to be a balance between velocity and airflow for the cubic inches serviced. In reality i think its more important to have a good running car thats still fun to drive than to have biggest and badest of everything - but runs like poopie on the street.

My 2 cents is it is fairly easy to get to 450hp with any of the better heads. But to go higher needs heads that match the rest your engine parts. Believe it or not the exh scavenging has much more effect than intake runner length/air charge tuning. Even the best heads can be choked by a restrictive exh sys.

Good night all,