SBF 4.125 bore O-rings??

[7secTurboLX]

Originally Posted by TurboII

Boost pressure is a measure of resistance to flow. Cylinder pressure is what determines HP no matter how you get there. As an example let's say a 400cfm head on 20psi makes 1500hp and a 325cfm head on the same engine at 35psi makes 1500hp. The chamber pressure is the same. If you can't hold the gasket at 35psi and have the heads ported to move more mass flow at lower boost you are still going to have the same problem around that same power level regardless of what boost pressure got you there.

Great point! I was just thinking about that. Cylinder pressure is cylinder pressure, the boost psi is irrelevant.

I've decided to resurface my block and heads to 30 Ra or better and try the Cometic MLX head gaskets. I'm going to retorque after a heat gun heat cycle on the motor stand, and then take a look at my tune again.

I was running 21 deg total timing at 25 psi on C16. I figured that was fairly conservative considering the fuel I'm running and that my compression is around 9.6 to 1. I definitely have some ET to be had by launching with more boost and playing with the suspension a bit. My 8.46 pass was made launching at only 4 psi and with some converter slip on top end.

I was going to send my heads and intake out for CNC porting, but I'm running the Gen 1 (Older than dirt) Victor JR heads and I don't want to drop a bunch of money into a head that might crack down the road.

[NONVTEC]

Timing isn't always what it appears. I had friend that bought a car that was a turbo SBF on Holley that was tuned by a well known "professional" tuner... Every time the previous owner took it out it blew a HG. They blamed it on it being a SBF. The car was on Q-16. I switched it over to E-85 and I CHECKED ACTUAL TIMING. At at idle it was advanced 3 degrees at 4000 rpm it was 12 degrees advanced. I fixed the timing in the ECU after 3 years and 100 runs it never blew another HG and went much faster then before.

Always double check timing and make sure you check inductive delay aswell. A lot of people overlook it.

[TurboII]

I have a customer running a set of those heads that are hand ported and yes OLDER THAN DIRT, LOL!! Its a 8.200 deck 365cuin in a all steel, full interior foxbody coupe complete with back seat and stock non-adjustable suspension with some bolt on relocation brackets. It has run in the 4.60's after I put Top Fuel Hoops, aluminum rods and converted it to methanol. It runs in the .114-.116 range on 60ft and has launched with as much as 22lbs of boost. It also has a Turboglide with 1.47 1st gear without which there is no chance of launching with that much power. Well over 100 passes without any gasket issues with wet block and heads.

[7secTurboLX]

Originally Posted by NONVTEC

Timing isn't always what it appears. I had friend that bought a car that was a turbo SBF on Holley that was tuned by a well known "professional" tuner... Every time the previous owner took it out it blew a HG. They blamed it on it being a SBF. The car was on Q-16. I switched it over to E-85 and I CHECKED ACTUAL TIMING. At at idle it was advanced 3 degrees at 4000 rpm it was 12 degrees advanced. I fixed the timing in the ECU after 3 years and 100 runs it never blew another HG and went much faster then before.

Always double check timing and make sure you check inductive delay aswell. A lot of people overlook it.

Definitely...Something I have never done is actual check engine "true" TDC. And yes, I'm guilty of NOT degreeing my cam in...just threw it in straight up! LOL! I'm going to degree it this time though.

That is just down right a scary thought that the timing could be that far off...WOW!

[7secTurboLX]

Originally Posted by TurboII

I have a customer running a set of those heads that are hand ported and yes OLDER THAN DIRT, LOL!! Its a 8.200 deck 365cuin in a all steel, full interior foxbody coupe complete with back seat and stock non-adjustable suspension with some bolt on relocation brackets. It has run in the 4.60's after I put Top Fuel Hoops, aluminum rods and converted it to methanol. It runs in the .114-.116 range on 60ft and has launched with as much as 22lbs of boost. It also has a Turboglide with 1.47 1st gear without which there is no chance of launching with that much power. Well over 100 passes without any gasket issues with wet block and heads.

Wish you were closer...I'd bring my block down to you to see if we could fit the receiver grooves into it for the Top Fuel hoops in the heads.

I'm going to run the MLX gaskets for now and hope for a 200 mph tailwind to push me into the 7s! LOL!

[TurboII]

As stated above, correct timing, both static and spark tables will make or break you trying to get +100% out of a 10 bolt head setup on a SB regardless of which OEM. Generally speaking rpm is your friend and stands a much better chance of meeting or exceeding your goals as long as the parts are up to the task. Lugging them below 7000rpm trying to "save" them is a big part of bending rods, breaking cranks, pushing out gaskets etc.

[Wheelsup302]

My combo is exactly yours Dart Shp 4.125 block. With o ring's and clark copper head gaskets. Re torque is key. On M1 and only 23 lbs of boost we just went [email protected]
Old ass vic jrs, steel rod 363. Tons left in the combo also. 110 % you can O ring yours.

[turbohatch88]

Originally Posted by Wheelsup302

My combo is exactly yours Dart Shp 4.125 block. With o ring's and clark copper head gaskets. Re torque is key. On M1 and only 23 lbs of boost we just went [email protected]
Old ass vic jrs, steel rod 363. Tons left in the combo also. 110 % you can O ring yours.

Which turbo are you using?

[Mike Beck]

Originally Posted by TurboII

As stated above, correct timing, both static and spark tables will make or break you trying to get +100% out of a 10 bolt head setup on a SB regardless of which OEM. Generally speaking rpm is your friend and stands a much better chance of meeting or exceeding your goals as long as the parts are up to the task. Lugging them below 7000rpm trying to "save" them is a big part of bending rods, breaking cranks, pushing out gaskets etc.

Here here!

People seem to forget about actually CHECKING the timing on an EFI engine! Especially the LS and LT1 clowns, they think everything is automatically spot-on.

The new Holley ECM's are nice, but you MUST check the timing! Learn how to do it, or find someone that does! Typically all the installs I have done or seen, the timing RETARDS with RPM with a new setup. There have been a few that advanced though, and that can really break shit in a high power setup!

Felpro (the original FAST) had the Inductive Delay function in them back in the 80's, and people didn't know what to do. Seems like many have still not learned........ Simple to do, only have to do it once unless you change your crank pickup stuff, like going from a magnetic (VR sensor) to a Hall Effect, etc.......

[sleeperstang]

Originally Posted by turbohatch88

Which turbo are you using?

I tune his car, and ironically we ran MLS gaskets up until this season. We changed them because we were gonna dry deck the heads anyways and figured it was a good time to oring/receiver groove it. We never had issues with the old mls gaskets. He ran an old used s480 tractor turbo (literally it still had some orange paint on it) and we went 4.8x at 149mph at 2900lbs roughly. This season he has made a switch to a 85mm Work turbo based on the borg s480 but we have yet to put very much co2 to it. One real “get acquainted outing” and she’s already bested his personal best.