In the process of replacing the expired 403" in my 1978 Delta 88 with a 455 , the build is in process and is as follows - .030 over , Keith Black KB277 Piston 15CC Dish , Piston is .006" in the hole , Cam 224 intake / 234 exh @ .050 ..... INT. 107 EXH 117 LOBE CENTERS , 496 INT. LIFT .520 EXH. LIFT , Speedmaster heads 80 CC had machine shop do 30 degree back cut on intake valves , I do have a set of NOS factory shim style headgasket set - not sure if they would be a good choice with the Speedmaster heads . Should I go with Cometic multi. shim type headgaskets ? if so what thickness ?....
What will my final compression be ( with Cometics ? with NOS shim style headgasket ? think they're .017" looking for 10 to 1 compression ........ I am going to use the original Quadrajet ( 800 CFM ) which I am going to rebuild . Will be using Edelbrock Performer intake ..... I also have a Edlebrock Torker but think the Performer would be a better choice for this combo - primarily will be street driven.

Finally any Idea on horsepower / torque with this combo ?

THX in advance

 

I use the summit racing compression calculator . Just put in your numbers and it will give you your ratio . using your numbers I come up with just about 10 to 1 using the fel pro .040 gasket and about 10.2 to 1 using the cometic .027 thick gasket . My opinion is the cometic is a better gasket but much more money . The cometic is available in other thicknesses.as far hp and torque I could only guess over 400 hp and over 500 ft lbs of torque . You have a similar build as mine I never had it on a dyno but it sure is a blast to drive on the street .I am just an amateur here so I hope I’m not steering you wrong . Good luck with your build !

 

With a .040 thick gasket about 9.9:1. Use the Mahle 55047. Same as a Cometic and 2/3 the price.
Cam choice ain’t great but….

 

If I remember correctly, stock heads were in the range of 80 -82 cc from the factory . I don't think the back cut on the intake valves will make a significant change in volume. With the NOS shim head gasket you should be good on static compression of about 10.25:1 - with your cam selection you should be good to go with 93 octane pump gas depending on the advance curve in your distributor and jetting in the Qjet. The Performer is a good choice for street driving - I have a torker on a 455 in my 68 442, really comes alive at about 3000 rpm. The performer on a 350 in my 66 F85 ( 64 cc heads with flat top pistons) is more responsive for part throttle/street driving. Have fun, sounds like a nice build.

 

I have a set of G heads that measured 83-84 cc. 80 would be really nice, but oh well.

 

Thanks for the input guys ordered Mahle headgaskets .040 . Working on the bottom end I have between .008" & .016" rod side clearance ( I know the highest recommended clearance is .014" for steel rods ) do you think this would cause any issues ?

Also I have a Thorton 5 qt pan and plan on using a Mondello crank scraper ( the kind that bolts to #2 & #4 main cap I am using main studs not bolts ) I assume I will need to have some sort of spacer between the main stud nut & the crank scraper on #2 & #4 as the top of #3 main cap studs are contacting the scraper ?

Thanks again for your input.